noun 2.any
object, action, event, pattern, etc., that conveys a meaning.
3.a conventional or arbitrary mark, figure, or symbol used as an
abbreviation for the
word or words it represents.
4.a motion or gesture used to express or convey an idea, command,
decision, etc.:
Her nod was a sign that it was time to leave. 5.a notice, bearing a
name, direction, warning, or advertisement, that is displayed or posted for public view:
a traffic sign; a store sign. EXPAND6.a trace; vestige: There wasn't a sign of them.
7.an arbitrary or conventional symbol used in musical notation to indicate tonality, tempo, etc.
8.Medicine/Medical. the objective indications of a disease.
9.any meaningful gestural unit belonging to a sign
language.
10.an omen; portent: a sign of approaching decadence.
13.Usually, signs. traces, as footprints, of a wild animal.
14.Mathematics. e.a symbol, as

or !, used to indicate a radical or factorial operation.
COLLAPSE verb (used with object) 17.to engage by written agreement: to sign a new player.
19.to communicate by means of a sign;
signal: He signed his wish to leave. EXPAND21.Obsolete. to direct or appoint by a sign.
COLLAPSE verb (used without object) 22.to write one's
signature, as a token of agreement, obligation,
receipt, etc.:
to sign for a package. 23.to make a sign or
signal: He signed to her to go away. 25.to obligate oneself by
signature: He signed with another team for the next season. Verb phrases26.sign away/over, to assign or dispose of by affixing one's signature to a document: She signed over her fortune to the church.
27.sign in, to record or authorize one's arrival (or departure) by signing a register. Also, sign out.
28.sign off, a.to withdraw, as from some responsibility or connection.
b.to cease radio or television broadcasting, especially at the end of the day.
c.Informal. to become silent: He had exhausted conversation topics and signed off.
d.to indicate one's approval explicitly if not formally: The president is expected to sign off on the new agreement.
29.sign on, b.to bind oneself to work, as by signing a contract: He signed on as a pitcher with a major-league team.
c.to start radio or television broadcasting, especially at the beginning of the day.
d.Computers. log1 (def. 17a). 30.sign up, to enlist, as in an
organization or group; to register or subscribe:
to sign up for the navy; to sign up for class.
Origin:
1175–1225; (noun) Middle English signe < Old French < Latin signum mark, sign, ensign, signal, image; (v.) Middle English signen to mark with a sign, especially the sign of the cross < Old French signer < Latin signāre to mark with a sign, inscribe, affix a seal to, derivative of signum
Related formssign·less, adjective
sign·like, adjective
post·sign, verb (used with object)
un·signed, adjective
Can be confused: sign, sing (see synonym note at
the current entry).
Synonyms
1. trace, hint, suggestion. 1, 4. signal. 10. indication, hint, augury. Sign, omen, portent name that which gives evidence of a future event. Sign is a general word for whatever gives evidence of an event—past, present, or future: Dark clouds are a sign of rain or snow. An omen is an augury or warning of things to come; it is used only of the future, in general, as good or bad: birds of evil omen. Portent, limited, like omen, to prophecy of the future, may be used of a specific event, usually a misfortune: portents of war.