signal

plural signals · alternative signall

1. A sequence of states representing an encoded message in a communication channel.
2. Any variation of a quantity or change in an entity over time that conveys information upon detection.
3. A sign made to give notice of some occurrence, command, or danger, or to indicate the start of a concerted action.

   All obeyed / The wonted signal and superior voice / Of this great potentate.

   1667, John Milton, “Book V”, in Paradise Lost. […], London: […] [Samuel Simmons], and are to be sold by Peter Parker […]; [a]nd by Robert Boulter […]; [a]nd Matthias Walker, […], →OCLC; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873, →OCLC

   1 more example

   Banner-Repeater signals tend to be provided in locations where drivers receive insufficient warning of the main signal, thereby effectively increasing the sighting distance for the main signal.

   2020 December 30, David Allen, “Unusual signals...”, in Rail, page 64

4. An on-off light, semaphore, or other device used to give an indication to another person.
   1. A railway signal.
5. InternetTVusuallycommunicationsAn electromagnetic action, normally a voltage that is a function of time, that conveys the information of the radio or TV program or of communication with another party.

   My mobile phone can't get a signal in the railway station.

6. An action, change or process done to convey information and thus reduce uncertainty.
7. A token; an indication; a foreshadowing; a sign.

   There was not the least signal of the calamity to be seen.

   1722, Daniel Defoe, A Journal of the Plague Year

   2 more examples

   The weary sun […] / Gives signal of a goodly day to-morrow.

   c. 1593 (date written), William Shakespeare, “The Tragedy of Richard the Third: […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act V, scene iii]

   Did I get it wrong all along? / You were sending signals / You sent certain signals to me

   2023, Róisín Murphy, “Hurtz So Bad”, in Hit Parade

8. Useful information, as opposed to noise.

   Antonyms: noise

9. UnixcomputingA simple interprocess communication used to notify a process or thread of an occurrence.
10. biochemistryA signalling interaction between cells.

present singular third person signals · US participle present signaling · UK participle present signalling · US participle past signaled · US past signaled · UK participle past signalled · UK past signalled · alternative signall

1. ambitransitiveTo indicate; to convey or communicate by a signal.

   I signalled my acquiescence with a nod.

   5 more examples

   He whistled to signal that we should stop.

   My arms wheeled frantically in the air as I tried to signal for help.

   In order to accommodate the new platform 4 and the reversibly signalled slow line, a deep cutting had to be cut back and held up in places with a concrete retaining wall.

   1962 June, David Walters, “The new station and layout at Coventry”, in Modern Railways, page 405

   I signaled for our waiter and ordered two Glenlivets, the only single malt they had behind the bar.

   2015, Andy Nottenkamper, A Rule Not Followed

   It is the latest step towards an airline-style advance booking-only system, which rail users have denounced as signalling the end of affordable, immediate travel.

   2024 February 7, Mel Holley, “Network News: LNER ditches Off-Peak for 70min semi-flexible fare”, in RAIL, number 1002, page 6

2. transitiveTo communicate with (a person or system) by a signal.

   Seeing the flames, he ran to the control room and signalled headquarters.

alternative signall

1. not comparableStanding above others in rank, importance, or achievement.

   a signal exploit; a signal success; a signal act of benevolence

   2 more examples

   As ſignal now in low dejected ſtate, / As earſt in higheſt, behold him where he lies.

   1671, John Milton, “Samson Agonistes, […].”, in Paradise Regain’d. A Poem. In IV Books. To which is Added, Samson Agonistes, London: […] J[ohn] M[acock] for John Starkey […], →OCLC, page 27

   But, setting this view aside, dishonorable would it be in the South were she willing to abandon to shame the memory of brave men who with signal personal disinterestedness warred in her behalf, though from motives, as we believe, so deplorably astray.

   1866, Herman Melville, Battle-Pieces and Aspects of the War, Supplement

   Synonyms: eminent, noteworthy, significant, notable