a token; indication.

any object, action, event, pattern, etc., that conveys a meaning.

a conventional or arbitrary mark, figure, or symbol used as an abbreviation for the word or words it represents.

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.

a notice, bearing a name, direction, warning, or advertisement, that is displayed or posted for public view

a traffic sign; a store sign.

a trace; vestige

There wasn't a sign of them.

an arbitrary or conventional symbol used in musical notation to indicate tonality, tempo, etc.

Medicine/Medical . the objective indications of a disease.

any meaningful gestural unit belonging to a sign language.

an omen; portent

a sign of approaching decadence.

sign of the zodiac.

sign language ( def. 1 ) .

Usually, signs. traces, as footprints, of a wild animal.

Mathematics .

a plus sign or minus sign used as a symbol for indicating addition or subtraction.

a plus sign or minus sign used as a symbol for indicating the positive or negative value of a quantity, as an integer.

multiplication sign.

division sign.

a symbol, as or !, used to indicate a radical or factorial operation.

to affix a signature to

to sign a letter.

to write as a signature

to sign one's name.

to engage by written agreement

to sign a new player.

to mark with a sign, esp. the sign of the cross.

to communicate by means of a sign; signal

He signed his wish to leave.

to convey (a message) in a sign language.

Obsolete . to direct or appoint by a sign.

to write one's signature, as a token of agreement, obligation, receipt, etc.

to sign for a package.

to make a sign or signal

He signed to her to go away.

to employ a sign language for communication.

to obligate oneself by signature

He signed with another team for the next season.

sign away or over, to assign or dispose of by affixing one's signature to a document

She signed over her fortune to the church.

sign in (or out ) to record or authorize one's arrival (or departure) by signing a register.

sign off,

to withdraw, as from some responsibility or connection.

to cease radio or television broadcasting, esp. at the end of the day.

Informal . to become silent

He had exhausted conversation topics and signed off.

to indicate one's approval explicitly if not formally

The president is expected to sign off on the new agreement.

sign on,

to employ; hire.

to bind oneself to work, as by signing a contract

He signed on as a pitcher with a major-league team.

to start radio or television broadcasting, esp. at the beginning of the day.

Computers . log 1 (def. 17a).

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.

noun

assurance , augury , auspice , badge , beacon , bell , caution , clue , divination , flag , flash , foreboding , foreknowledge , foreshadowing , foretoken , forewarning , gesture , giveaway , handwriting on wall , harbinger , herald , high sign * , hint , light , manifestation , mark , nod , note , omen , portent , precursor , prediction , premonition , presage , presentiment , prognostic , proof , signal , suggestion , symbol , symptom , token , trace , vestige , warning , wave , whistle , wink , board , character , cipher , crest , device , emblem , ensign , guidepost , insignia , logo , notice , placard , representation , signboard , signpost , symbolization , type , evidence , index , indication , indicator , signification , stamp , witness , gesticulation , motion , bill , billboard , poster , forerunner , prefigurement , prognostication , adumbration , criterion , escutcheon , hieroglyph , indicia , indicium , logogram , logograph , monogram , prodigy , shingle , signature

verb

acknowledge , authorize , autograph , confirm , endorse , initial , ink , inscribe , put john hancock on , put john henry on , rubber-stamp , set one’s hand to , signature , subscribe , witness , beckon , express , flag , gesticulate , gesture , indicate , motion , signal , signalize , signify , use sign language , wave , undersign , advertisement , aries , auspice , badge , banner , betoken , billboard , brand , clue , constellation , countersign , cue , demonstration , denotation , denote , earmark , emblem , enter , evidence , expression , extol , figure , guidepost , harmonize , hint , image , index , indication , indicator , insignia , lullaby , mark , message , neon , nod , note , omen , portent , poster , premonition , presage , proclaim , prognostic , proof , standard , suggestion , symbol , tattle , token , trace , underwrite , vestige , vocalize , warning

phrasal verb

enlist , enroll , enter , muster in , sign up , cede , deed , grant , make over