What English uses it for now
In ordinary English a sign can be a board on a shop, a gesture instead of speech, a plus or minus in algebra, a clinician’s objective finding, one of the twelve zodiac divisions, or the tracks an animal leaves on a trail. The uses look scattered until they are read together: each is something that stands for a fact, a command, or a meaning that is not itself on the surface.
That spread is old. Latin had already packed mark, token, signal, omen, and military standard into one noun. English did not invent the cluster; it inherited it, then kept adding jobs.
The origin of the word sign is not a single borrowing at one date. The same Latin stem reached English twice, once in Old English and again, more decisively, through French in the Middle English period.
Two roads from Latin
By the early thirteenth century Middle English had signe, taken from Old French signe. That French noun continues Latin signum, which covered an identifying mark, a proof, a symbol, a military ensign, a signal, an omen, and a constellation. The first firmly dated English sense is narrower: a motion of the hand meant to convey an idea.
English had already met the Latin word. Old English seġn, a direct loan, meant a mark, a token, or especially a banner. So the later everyday noun sat on two Latin-derived streams: an older clerical and military loan, and a French-shaped form that became the default spelling and pronunciation. Modern dictionaries treat the result as partly French and partly Latin. Along the way the word crowded out much of the native Germanic token, which survives with a tighter range — a keepsake, a symbolic object, a piece of evidence offered in support of a claim.
The verb has the same layered history. Early thirteenth-century signen, to make the sign of the cross, continues both Old English seġnian and Old French signer / signier. All of those go back to Latin signare: to set a mark on, stamp, designate, or, by extension, to point something out.
The Latin noun and a disputed root
Past Latin the trail splits. One account, long associated with Calvert Watkins and still reflected in some standard dictionaries, takes signum as a standard that one follows, built on the Indo-European root for follow (the family of Latin sequor). On that view the military ensign is the prototype: the object the ranks keep in view.
Another account, argued in detail by Michiel de Vaan, ties the word to the root behind Latin seco, to cut. A sign would then have begun as something cut or carved out, a physical incision, and only later become any identifying token. De Vaan also records a comparison with Hebrew and Aramaic words for a slaughtering knife and the suggestion that Latin and those Semitic terms might share an unknown third source, which would lift the story out of Indo-European altogether.
Recent work on Sabellic relatives, including Oscan segnúm in the sense of a statue, has reopened the follow-root as the better phonological fit for both Latin and Sabellic, and has pointed to Germanic forms such as Gothic siuns, sight or appearance, where follow already shades into visual tracking. The disagreement is genuine; a tidy single ancestor should not be treated as settled. What is settled is the Latin noun and the English family grown from it: signal, signature, signify, assign, design, resign, ensign.
Senses that accumulated in English
Once signe was at home, further meanings arrived in a fairly clear order rather than all at once. By the late thirteenth century the noun could name a visible device with a special meaning, and also a token of some condition. Around 1300 it could be an omen, a coming event read in advance, or a miracle taken as a demonstration of divine power. By the mid-fourteenth century it belonged to the zodiac: one of the twelve divisions of the sky.
The hanging board that many speakers now think of first is later. Mid-fifteenth-century English uses the word for an inscribed panel on an inn or shop, hung so that one building could be told from the next. In the 1550s it appears for conventional marks that stand in for words, as in music or mathematics. In a few uses the noun is probably a shortening of ensign, the banner sense already present in Latin.
The verb’s later path is equally concrete. Marking or stamping is attested from the mid-fourteenth century; putting one’s name to a document from the late fifteenth. Communicating by a significant motion of the hands is recorded from about 1700, the line that now includes signed languages as full linguistic systems. American baseball’s transitive use, to engage a player by contract, is a late-nineteenth-century extension of the signature sense. Mid-twentieth-century phrasal verbs such as sign out, to leave a written record of departure, apply that same writing-one’s-name core to everyday bookkeeping.
What to keep from the history
French signe, Italian segno, Spanish signo, and Portuguese sinal are siblings, all continuing Latin signum. English signal is a doublet that arrived by a different French route. Native token was never erased; it simply lost the general job of indication, while sign took on boards, gestures, mathematics, medicine, and the sky.
The fact worth carrying away is the military standard inside the Latin stem. Whether that standard is something the eye follows or something originally cut into wood or metal, English still uses one short noun for a banner, a shop fascia, a doctor’s finding, and a plus mark, because Latin had already bundled mark, signal, omen, and ensign into a single word.