anything that serves to indicate, warn, direct, command, or the like, as a light, a gesture, an act, etc.: a traffic signal; a signal to leave.
anything agreed upon or understood as the occasion for concerted action.
an act, event, or the like that causes or incites some action: The unjust execution was the signal for revolt.
a token; indication.
Electronics. an electrical quantity or effect, as current, voltage, or electromagnetic waves, that can be varied in such a way as to convey information.
Cards. a play that reveals to one's partner a wish that he or she continue or discontinue the suit led.
adjective
serving as a signal; used in signaling: a signal flag.
unusual; notable; outstanding: a signal exploit.
verb (used with object),sig·naled,sig·nal·ing or (especially British)sig·nalled,sig·nal·ling.
to make a signal to.
to communicate or make known by a signal.
verb (used without object),sig·naled,sig·nal·ing or (especially British)sig·nalled,sig·nal·ling.
to make communication by a signal or signals.
Origin of signal
1350–1400;Middle English (noun) < Medieval Latinsignāle,Late Latin, noun use of neuter of signālis of a sign. See sign, -al2, -al1
Related formssig·nal·er; especially Britishsig·nal·ler, nounpre·sig·nal, noun, verb (used with object),pre·sig·naled,pre·sig·nal·ing or (especially British)pre·sig·nalled,pre·sig·nal·ing.re·sig·nal, verbre·sig·naled,re·sig·nal·ing or (especially British)re·sig·nalled,re·sig·nal·ling.un·sig·naled, adjectiveun·sig·nalled, adjectiveCan be confusedsignalsingle
any sign, gesture, token, etc, that serves to communicate information
anything that acts as an incitement to actionthe rise in prices was a signal for rebellion
a variable parameter, such as a current or electromagnetic wave, by which information is conveyed through an electronic circuit, communications system, etc
late 14c., "visible sign, indication," from Old French signal, seignal "seal, imprint, sign, mark," from Medieval Latin signale "a signal," from Late Latin signalis (adj.) "used as a signal, pertaining to a sign," from Latin signum "signal, sign" (see sign (n.)). Restricted sense "agreed-upon sign (to commence or desist, etc.) is from 1590s. Meaning "modulation of an electric current" is from 1855.
adj.
"remarkable, striking, notable" ("serving as a sign"), 1640s, from French signalé, past participle of signaler "to distinguish, signal" (see signal (n.)).
v.
1805, "to make signals to," from signal (n.). Related: Signaled; signaling. Earlier verb was signalize (1650s).
A fluctuating quantity or impulse whose variations represent information. The amplitude or frequency of voltage, current, electric field strength, light, and sound can be varied as signals representing information.
