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signal

[sig-nl]
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noun
  1. 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.
  2. anything agreed upon or understood as the occasion for concerted action.
  3. an act, event, or the like that causes or incites some action: The unjust execution was the signal for revolt.
  4. a token; indication.
  5. Electronics. an electrical quantity or effect, as current, voltage, or electromagnetic waves, that can be varied in such a way as to convey information.
  6. Cards. a play that reveals to one's partner a wish that he or she continue or discontinue the suit led.
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adjective
  1. serving as a signal; used in signaling: a signal flag.
  2. unusual; notable; outstanding: a signal exploit.
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verb (used with object), sig·naled, sig·nal·ing or (especially British) sig·nalled, sig·nal·ling.
  1. to make a signal to.
  2. to communicate or make known by a signal.
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verb (used without object), sig·naled, sig·nal·ing or (especially British) sig·nalled, sig·nal·ling.
  1. to make communication by a signal or signals.
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Origin of signal

1350–1400; Middle English (noun) < Medieval Latin signāle, Late Latin, noun use of neuter of signālis of a sign. See sign, -al2, -al1
Related formssig·nal·er; especially British sig·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, verb re·sig·naled, re·sig·nal·ing or (especially British) re·sig·nalled, re·sig·nal·ling.un·sig·naled, adjectiveun·sig·nalled, adjective
Can be confusedsignal single

Synonyms

See more synonyms for signal on Thesaurus.com
1, 4. sign. 8. unique, exceptional, remarkable, striking.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for signal

Contemporary Examples

Historical Examples

  • As she spoke, Geta lifted the curtain, and Philothea instantly obeyed the signal.

    Philothea

    Lydia Maria Child

  • Each instinctively touched the other's arm, as a signal for silence.

    Philothea

    Lydia Maria Child

  • For months I had received daily and hourly the most signal benefits from his hands.

  • The appearance of Mr. Gladstone was the signal for great applause.

    The Grand Old Man

    Richard B. Cook

  • Cissy sent her a look, a signal, and rose; she stood by the doorway.

British Dictionary definitions for signal

signal

noun
  1. any sign, gesture, token, etc, that serves to communicate information
  2. anything that acts as an incitement to actionthe rise in prices was a signal for rebellion
    1. a variable parameter, such as a current or electromagnetic wave, by which information is conveyed through an electronic circuit, communications system, etc
    2. the information so conveyed
    3. (as modifier)signal strength; a signal generator
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adjective
  1. distinguished or conspicuous
  2. used to give or act as a signal
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verb -nals, -nalling or -nalled or US -nals, -naling or -naled
  1. to communicate (a message, etc) to (a person)
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Derived Formssignaller or US signaler, noun

Word Origin

C16: from Old French seignal, from Medieval Latin signāle, from Latin signum sign
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for signal

n.

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.

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adj.

"remarkable, striking, notable" ("serving as a sign"), 1640s, from French signalé, past participle of signaler "to distinguish, signal" (see signal (n.)).

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v.

1805, "to make signals to," from signal (n.). Related: Signaled; signaling. Earlier verb was signalize (1650s).

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Online Etymology Dictionary, © 2010 Douglas Harper
signal in Science

signal

[sĭg′nəl]
  1. 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.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.