98 Fun Facts About Signs and Symbols

Mr. Yuk, a green grimacing face, was put on US poison labels because children linked the skull and crossbones to what?

Pirates had made the skull and crossbones look like fun, so the Pittsburgh poison centre tried faces on young children and picked the one they liked least.

The three chasing arrows of the recycling symbol, drawn by 23-year-old student Gary Anderson, trace what shape?

A Möbius strip is what the arrows fold into; the Container Corporation of America, whose 1970 contest Anderson won, never held a trademark on it, so anyone anywhere may use the symbol.

Often said to mean 'save our souls', what was SOS really when it became the distress call in 1906?

A distinctive Morse sequence, three dots, three dashes, three dots, was picked because it is easy to send and hard to mistake; the 'save our souls' reading was invented afterwards.

The European Commission says the two parallel lines through the euro sign stand for what quality?

Stability is the official reading of the double bar, while the curve around it is a Greek epsilon, chosen to echo the first letter of the word Europe.

Which Swedish naturalist first used the Mars and Venus symbols to mark male and female flowers, in the 1750s?

Carl Linnaeus, sorting flowers by their stamens and pistils, was first to press the astronomers' planet signs into service for the sexes, and biology has kept them ever since.

Susan Kare lifted the ⌘ on Apple's Mac keyboards from a road sign used in Nordic countries to mark what?

Places of interest is what the looped square marks on Nordic roads; Kare found it in a symbol dictionary after Steve Jobs vetoed filling the Mac's menus with Apple logos.

The two-snake caduceus on US Army medical insignia is, in Greek myth, the staff carried by which god?

Hermes, god of trade and messengers, carries the caduceus; its adoption for US Army medical officers in 1902 spread the mix-up with the single-snake rod of Asclepius, medicine's older emblem.

The red and white barber's pole recalls which medical service that barbers once offered?

Bloodletting is the trade behind the stripes, red for blood and white for bandages; the pole itself is said to recall the stick a patient squeezed to make the veins stand out.

Which engineer chose the @ sign in 1971 to split a user's name from a host in the first networked email?

Ray Tomlinson of BBN picked the little-used @ key, a mark that had spent centuries as an abbreviation for the arroba, a Spanish weight of about 25 pounds.

The % sign grew out of a scribe's looped shorthand for 'per cento', a phrase in which language?

Italian 'per cento', for a hundred, was written so often that it shrank to 'pc' with a small loop; by about 1650 the mark looked like a fraction, and the 'per' then dropped away.

Gerald Holtom drew the circle-and-lines peace symbol in 1958 for an Aldermaston march by a British campaign for what?

Nuclear disarmament's initials N and D, as sent by flag semaphore, are superimposed in the design Holtom presented to the Direct Action Committee in February 1958.

Masahiro Hara, inventor of the QR code at Denso Wave in 1994, modelled its black-and-white squares on which board game?

Go's black and white stones gave Hara the idea during a lunchtime game; he needed a label for car parts that held far more than the 20 or so characters a barcode could carry.

Which tech standard's logo binds the runes Hagall and Bjarkan, the initials of a 10th-century Viking king?

Bluetooth's logo joins the runes for H and B, for King Harald Bluetooth, who brought separate peoples under one crown much as the standard was meant to unite PCs and phones; the name began as a stopgap codename.

Which artist's lithograph of a dove, made after World War II, turned the bird into a secular symbol of peace?

Pablo Picasso's Dove was chosen for the poster of the 1949 Paris Peace Congress, and when his daughter was born as the congress opened he named her Paloma, Spanish for dove.

Harvey Ball drew the yellow smiley face in 1963 to lift morale after a merger at a Worcester firm in what business?

Life insurance was the trade: State Mutual wanted a little smile to cheer its staff, and Ball drew one in ten minutes for $45 and never trademarked it.

The three-crescent symbol a Dow Chemical engineer devised in 1966 to be 'memorable but meaningless' warns of what?

Biohazards got a sign with no earlier meaning on purpose: Charles Baldwin wanted a shape people would remember but could not misread, so that its meaning could be taught from scratch.

The radiation trefoil was drawn in 1946 at the Radiation Laboratory of which university, originally in magenta?

Berkeley's Radiation Laboratory staff doodled it out in 1946 and printed it on blue, chosen because so little blue was used where radioactive work went on; high-visibility yellow later took over.

Under the UN's Globally Harmonized System, chemical hazard pictograms sit inside a frame of what shape and colour?

A red diamond frames a black symbol on white in every country that adopts the system, which is why Europe retired its own older hazard symbols, a switch completed in 2017.

On the NFPA 704 hazard square posted at US chemical sites, what does the yellow quadrant rate?

Reactivity is yellow on the right, flammability red on top and health blue on the left, each scored from 0 to 4 so that firefighters can judge what a building holds before they enter.

The word 'clef', for the sign that opens a musical staff, is simply the French word for what?

Key is the French clef, and the name fits: the sign fixes one reference note on one line, unlocking every other line and space on the staff.

The treble clef, which curls around the second line of the staff, is a stylised form of which letter?

G is the letter the treble clef grew from, its curl circling the G above middle C; the bass clef is likewise a worn-down F and the alto clef a C.

In sheet music, 'D.S. al coda' sends the player back to which marking before the jump to the coda?

The segno is literally 'the sign', an S crossed by a diagonal stroke between two dots; D.S. abbreviates dal segno, 'from the sign', so the player repeats from there.

The white-and-blue Alpha signal flag warns nearby vessels of what?

A diver below means the vessel flying Alpha cannot move from its position, so others must keep well clear at slow speed; North American sport divers more often fly a red flag with a white diagonal stripe.

The 'Blue Peter', hoisted when a ship is about to leave port, is the signal flag for which letter?

P, or Papa, is the letter; the BBC named its children's programme Blue Peter after the flag in 1958, promising young viewers a voyage of adventure.

In motor racing, what does a black flag with an orange disc tell a driver to do?

Pit for a mechanical problem is the order: the car has serious trouble or loose bodywork that presents a risk to other competitors, so it is summoned in.

On a 1965 Beatles album cover, the band strike semaphore-style poses meant to spell which word, though they really read NUJV?

HELP, the album's title, was the plan, but photographer Robert Freeman thought the true arm positions looked wrong and rearranged them for the best shapes, so the British sleeve reads NUJV.

Pluto's astronomical symbol, announced by its discoverers in 1930, is a monogram of which two letters?

P and L stand for Pluto but also for Percival Lowell, whose observatory began the search for a planet beyond Neptune that eventually turned up Pluto.

Jérôme Lalande designed a symbol for Uranus as a globe topped with the initial of which astronomer?

William Herschel, the planet's discoverer, was told by Lalande it was 'a globe surmounted by the first letter of your name', and French almanacs for a time called the planet Herschel.

Urbain Le Verrier proposed which symbol for the planet he had predicted mathematically, falsely claiming official approval for it?

A trident, the sea god's weapon, was Le Verrier's pick for Neptune; he then sought to have the planet named Le Verrier, after himself, a name astronomers in other countries firmly resisted.

The star and crescent on Turkey's flag was an emblem of which ancient Greek colony long before the Ottomans captured it?

Byzantium, later Constantinople and now Istanbul, stamped the pair on its coins; legend ties them to a light in the night sky that exposed an attack by Philip of Macedon in 340 BC.

The six-pointed Star of David became a distinctive emblem of Jewish communities in the 17th century in which city?

Prague's Jewish community adopted the hexagram, two overlapping equilateral triangles, as its own, though the shape appears as mere decoration in synagogues from antiquity.

The 24-spoke navy-blue wheel at the centre of India's flag is named after which Indian emperor?

Ashoka's wheel comes from the lion capital of one of his pillars; in 1947 it replaced the spinning wheel on Gandhi's flag, partly, Nehru said, because it looks the same from both sides.

The ichthys, an early Christian emblem whose letters stand for 'Jesus Christ, God's Son, Saviour', is the Greek word for what?

Fish in Greek is ichthys, and its five letters open the five words of the phrase; Tertullian ran with the image, calling Christians 'little fishes' born in the water of baptism.

Which Egyptian hieroglyph meaning 'life' takes the form of a cross topped with a loop?

The ankh is held to a king's nose by the gods in Egyptian art, offering him the breath of life; Egypt's Coptic Christians later adapted its looped shape as a form of the cross.

The swastika's name comes from a word meaning 'conducive to well-being' in which ancient language?

Sanskrit svastika names an ancient cross-cultural sign used by many religions across Eurasia, millennia before its 20th-century appropriation in Europe.

Which paragraph mark did medieval rubricators paint in red to signal a new train of thought?

The pilcrow, ¶, began as a C for capitulum, 'little head'; when rubricators ran out of time the gaps left for it stayed blank, which is how the paragraph indent was born.

Dutch and Afrikaans speakers call the @ sign by a name that means the tail of which animal?

Monkey tail, apenstaartje in Dutch and aapstert in Afrikaans, suits the stroke that curls right round the a; Finns see a cat's tail in the same sign and Belarusians a snail.

The ampersand began as a scribes' ligature of which two-letter Latin word?

Et, Latin for 'and', had its E and T run together in Roman handwriting; the name ampersand came much later, slurred from 'and per se and', the phrase that once closed a recital of the alphabet.

Chris Messina borrowed the # sign from IRC chat channels in 2007 to propose grouping posts on which platform?

Twitter got the idea in a single tweet, and Messina never tried to patent the hashtag, writing that such things are 'born of the Internet, and should be owned by no one'.

Which punctuation mark, coined by Martin Speckter in 1962, fuses a question mark with an exclamation point?

The interrobang joins 'interrogation' to 'bang', printers' slang for an exclamation point; Speckter, an advertising man, wanted one mark for a surprised question, and Remington sold typewriters with it in 1968.

Which Welsh mathematician introduced = in 1557, choosing parallel lines because 'no two things can be more equal'?

Robert Recorde's The Whetstone of Witte used 'a paire of paralleles, or Gemowe lines' to avoid repeating 'is equalle to', just one year before his death.

William Oughtred, who gave us the × sign in his 1631 Clavis Mathematicae, is also credited with inventing what?

The slide rule came from Oughtred setting two of Edmund Gunter's logarithmic scales to slide against each other, which did away with the dividers once needed to read a single one.

The ISO 80000-2 standard says the ÷ sign 'should not be used' for division; which mark does it recommend instead?

The slash, formally the solidus, or a horizontal fraction bar is what the standard prefers; before Johann Rahn used ÷ for division in 1659, writers had used the very same mark for subtraction.

William Jones first wrote π for the circle ratio in 1706, but which mathematician's adoption of it made the letter standard?

Leonhard Euler adopted the letter some thirty years after Jones, whose notation other mathematicians had not taken up, and because Euler wrote to mathematicians all over Europe the symbol spread fast.

Shigetaka Kurita said his 1999 emoji drew on manga, Chinese characters, street signs and pictograms used for what?

Weather forecasts' pictograms fed Kurita's 176 emoji, each drawn on a 12-by-12-pixel grid; in 2016 New York's Museum of Modern Art took the whole set into its collection.

Apple's first iPhone emoji, added in November 2008, at first worked only with SIM cards from which country?

Japan's SoftBank customers alone got the keyboard at first; everyone else needed a third-party app to switch it on until Apple opened it to all with iOS 5 in 2011.

The 🔰 emoji copies the shoshinsha mark, a yellow-and-green chevron that must be displayed on cars by whom?

Beginner drivers must show it for a year after passing their test, and other motorists are forbidden to cut in on or crowd a car that carries it.

The wheelchair accessibility symbol began as a 1968 sketch by design student Susanne Koefoed, from which country?

Denmark's Koefoed drew a headless stick figure; Karl Montan's commission 'humanised' it with a circle for a head, and the result was adopted as the international symbol in 1969.

Student Carolyn Davidson was paid just $35 in 1971 to design the logo of which sportswear company?

Nike was the brand name that its makers, Blue Ribbon Sports, picked in 1971. The $35 covered 17.5 hours of work on the Swoosh, though Davidson is certain she put in more.

On the back of the US one-dollar bill, the Eye of Providence floats above an unfinished what?

Pyramid of thirteen steps, one for each original state, left unfinished to suggest a nation with room to grow. Both sides of the Great Seal have been printed on the bill since 1935.

The first product scanned with a UPC barcode, at an Ohio supermarket in 1974, was a pack of what?

Chewing gum, a ten-pack of Wrigley's Juicy Fruit, was simply the first thing picked out of the shopping cart in Troy, Ohio. A facsimile of the packet went on display at the Smithsonian.

Referee Ken Aston based football's yellow and red cards on the colours of which everyday objects?

Traffic lights gave Aston a code that crosses every language barrier: yellow for caution, red for stop. He was in charge of the referees at the 1966 World Cup.

On the UK's coat of arms, a crowned lion stands for England; which chained beast stands for Scotland?

Unicorn supporters once held up the arms of the Kings of Scots, and the animal suited them: it was believed to be the natural enemy of the lion.

Gilbert Baker's rainbow flag first flew in June 1978 at a Gay Freedom Day parade in which US city?

San Francisco saw two eight-stripe flags that day. Hot pink was soon dropped because the fabric was hard to find, and the design settled at six colours.

Which metal takes its chemical symbol Pb from plumbum, the Latin word that also gave English 'plumbing'?

Lead pipes were the first effective water pipes of the Roman era, so the whole pipe-fitting trade ended up named after the metal.

Pierre de Coubertin's Olympic rings, drawn in 1913, represent five of what, joined together by sport?

Continents, with the Americas counted as one. The idea that each colour belongs to a particular one came later; Coubertin meant only the number of rings to carry the meaning.

Which country flies the only non-rectangular national flag, two stacked pennants bearing a moon and a sun?

Nepal joined the pennons of two rival branches of its ruling dynasty into one flag. Until 1962 its sun and crescent moon were both drawn with human features.

The $ sign most likely grew out of 'ps', a shorthand that 1770s West Indies merchants used for which coin?

Peso coins, the 'pieces of eight' of British America, were also the model for the currency the United States adopted in 1792.

Which element takes its chemical symbol K from kalium, a name the Swedish chemist Berzelius championed in 1814?

Potassium was Humphry Davy's own name for the metal he isolated in 1807, and English kept it. Germanic languages adopted Kalium instead, which is where the K comes from.

The £ sign for the British pound grew out of the first letter of which Latin word for a Roman weight?

Libra gives the sign its ornate L. The word meant a pair of scales before it meant a weight, which is why the zodiac sign shares the name and a pound in weight is abbreviated lb.

Sagittarius, the archer of the Western zodiac, is commonly drawn as which half-human creature of Greek myth?

Centaur, half man and half horse, drawing a bow. Some ancient writers took the figure to be Chiron, tutor of Jason, though a rival tradition names a different archer altogether.

Which Greek letter is the symbol for the ohm, the unit of electrical resistance named after Georg Ohm?

Omega was suggested in 1867 simply because it sounds like 'ohm'. Older documents often printed the small form of the letter, raised beside the number.

The Red Cross emblem, a red cross on a white ground, was formed by reversing the colours of which country's flag?

Switzerland's flag turned inside out gave the emblem. During the Russo-Turkish War of 1877–78 the Ottoman Empire did the same with its own flag to create the Red Crescent.

On the Soviet hammer and sickle, the hammer stood for industrial workers; which group did the sickle represent?

Peasants and factory workers in alliance were the emblem's whole message. Burma's flag later made the same point with rice laid over a cogwheel.

The State of Israel's emblem centres on which ritual object, copied from a carving on the Arch of Titus in Rome?

Menorah lamps, with their seven branches, stood in the ancient Temple in Jerusalem and have been an emblem of Judaism since antiquity.

The fleur-de-lis, the heraldic emblem of the kings of France, is a stylised drawing of which flower?

Lily is what 'lis' means in French. The flower's link with purity made it a favourite of Christian art, where it is often shown with the Virgin Mary.

Saint Patrick is said to have used the three-leaved shamrock to explain which Christian doctrine to the Irish?

The Trinity story is not recorded anywhere until a 1726 work by the botanist Caleb Threlkeld, some thirteen centuries after Patrick's mission.

Which prickly plant became Scotland's emblem after, legend says, a barefoot Norse raider trod on one and cried out?

Thistle spines are said to have saved a sleeping Scottish camp from a night attack. By the 1470s the plant was appearing on the silver coins of King James III.

Ancient Egyptians wore amulets shaped like which insect, sacred to Khepri, the god who rolled the sun across the sky?

Scarab beetle habits explain the choice: the insects roll balls of dung along the ground, which Egyptians read as an image of the sun's daily journey from east to west.

Which disease's awareness emblem, a looped red ribbon, was first worn on screen by Jeremy Irons at the 1991 Tony Awards?

HIV/AIDS campaigners in a New York artists' caucus made the ribbon that year. They kept it free of copyright and refused to name any one person as its creator.

Which transport network's roundel began in 1908 as a solid red disc behind station names on platforms?

London Underground was not first with the shape: a London bus company registered a roundel trademark in 1905. By 1912 posters were printing the word Underground across the circle.

Three golden balls hanging from a bar, an emblem often traced to the Medici family, mark the shop of which trade?

Pawnbroker signs may borrow from Medici heraldry. One conjecture is that the balls began as flat gold coins and were rounded out to catch the eye.

For centuries the emblem of the Isle of Man, shown on its red flag, has been a triskelion of three what?

Legs joined at the thigh have stood for the island since at least the late 13th century. One suggestion is that the device came from Sicily, long tied to a similar emblem.

Mexico's coat of arms recalls the founding of Tenochtitlan with an eagle devouring a snake atop which plant?

Cactus of the prickly pear kind, to be exact. Europeans later read the scene as good triumphing over evil, with the snake standing in for the serpent of Eden.

Which emoji did Oxford Dictionaries choose as its Word of the Year for 2015?

Face with Tears of Joy was picked as the character that best reflected the ethos, mood and preoccupations of 2015. One Slate writer objected that it was less a word than a blank for readers to fill in.

On clothing care labels, where a washtub stands for washing, which plain shape tells you whether bleach may be used?

Triangle marks were once lettered Cl for chlorine. An empty one now allows any bleach, two slanting lines inside forbid chlorine, and a cross through it bans bleaching altogether.

Designer Rob Janoff said he put a bite in Apple's logo so that the fruit would not be mistaken for a what?

Cherry lookalikes were the worry, since a plain round fruit could be anything. The rainbow bands across his 1977 design advertised that Apple's computers had colour screens.

The ℞ sign on a prescription is a crossed capital R, abbreviating which Latin command to the pharmacist?

Recipe is a command meaning 'take', the first word a medieval physician wrote before listing what the apothecary should compound.

In a mathematical proof, the ∴ sign, three dots with one above two, is read as which word?

Therefore was the meaning Johann Rahn gave the upright dots in his 1659 algebra. Turned upside down, the same three dots make the 'because' sign.

Which operation is shown by an exclamation mark after a number, a notation Christian Kramp introduced in 1808?

Factorial means multiplying a whole number by every positive whole number below it, so 5! works out as 120.

Margaret Calvert drew Britain's school road sign, a girl and boy hand in hand; on whom did she model the girl?

Herself as a child, by her own account. Her 'farm animals' sign was drawn from life too: the model was a real cow called Patience.

Which African country's flag shows an AK-47 crossed by a hoe over an open book, for defence, production and education?

Mozambique's constitution speaks only of a gun. The model is never named, though it is generally understood to be an AK-47 with a bayonet attached.

Which Victorian MP, a campaigner against overloaded 'coffin ships', gave his name to the load line on ships' hulls?

Samuel Plimsoll, Liberal MP for Derby, took on owners who sent out unseaworthy vessels and risked their crews. The rubber-soled canvas shoe was later named after his line.

The six stars on carmaker Subaru's badge depict which star cluster in the constellation Taurus?

Pleiades is what the carmaker's name means, the cluster also called the Seven Sisters. Tradition says one sister is invisible, hence only six stars on the badge.

The horse at the centre of Porsche's crest comes from the coat of arms of which city, the carmaker's home?

Stuttgart takes its name from an old word for 'stud farm', because the city began around 950 as a duke's breeding ground for warhorses.

Which Los Angeles Lakers guard's dribbling silhouette did designer Alan Siegel use for the NBA logo in 1969?

Jerry West's outline was based on a photograph. The league would not confirm it, because, as Siegel put it, the NBA wanted the mark institutional, not individual.

In Egyptian hieroglyphs, the oval ring known as a cartouche shows that the signs inside it spell what?

A royal name got the oval as a protective ring, meant to guard the pharaoh from evil spirits in life and after death.

Louis Braille built his raised-dot alphabet at fifteen by improving Charles Barbier's tactile code, now known as what?

Night writing got that name only later, when the code was considered as a way for soldiers to communicate silently in the dark. Barbier's own writings never use the term.

South Korea's flag surrounds its red-and-blue taegeuk with four trigrams, three-line figures from which Chinese classic?

I Ching divination stacks two such trigrams into a six-line hexagram. The flag carries the four cardinal ones out of a possible eight.

Leonhard Euler believed the √ sign began as a letter r, the initial of which Latin word for 'root'?

Radix would make the sign a stretched letter r. It first reached print in 1525, without its overhead bar, in Christoff Rudolff's Die Coss.

Workers at which US research lab coined the name 'octothorp' for the # on the telephone keypad?

Bell Labs staff were adding an eleventh and a twelfth button to the phone keypad and needed a proper name for each new character.

Norm Cox drew the three-line 'hamburger' menu icon in 1981 for the Star, a personal computer from which company?

Xerox's potential users heard Cox joke that the icon was an air vent to keep the window cool. He meant it to be as simple as a road sign and to mimic the list it opened.

Scott Fahlman proposed :-) in September 1982 to mark jokes on an online message board at which university?

Carnegie Mellon's board needed a way to tell serious posts from jokes, so Fahlman offered a marker. A 1967 magazine article had floated a similar idea that was never put into practice.

Which Venetian printer issued Pietro Bembo's De Aetna, the 1496 book in which the semicolon is first attested?

Aldus Manutius, born Aldo Manuzio, founded the Aldine Press and introduced small portable books, the forerunners of the modern paperback.

Remembrance poppies were inspired by 'In Flanders Fields', a 1915 poem by which Canadian army doctor?

John McCrae wrote it on 3 May 1915, the day after a friend and fellow soldier was killed at Ypres. Moina Michael later promoted the flower as a memorial emblem.

On British hallmarks, the lion passant, a walking lion added to English marks in 1544, certifies which metal?

Sterling silver, 92.5% pure, became the required standard for English silverware under a statute of Edward I in 1300, which had tested pieces stamped with a leopard mark.

Lady Justice carries scales and a sword; which item, often added since the 16th century, signals her impartiality?

Blindfold imagery began as satire, showing Justice blind to the injustice carried on in front of her. Only later was it reinterpreted as a sign of even-handedness.

Which sacred syllable, written ॐ, opens and closes chapters of the Vedas and is chanted during meditation?

Om is also called the Pranava, and it is shared well beyond Hinduism: Buddhists, Jains and Sikhs use it as a mantra or invocation too.