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a. An indicator, such as a gesture or colored light, that serves as a means of communication. See Synonyms at gesture.
b. A message communicated by such means.
2. Something that incites action: The peace treaty was the signal for celebration.
3. Biology A physical entity, such as a chemical or an electromagnetic wave, that activates a cell receptor and elicits a specific response.
a. Electronics An impulse or fluctuating quantity, as of electrical voltage or light intensity, whose variations represent coded information.
b. Computers A sequence of digital values whose variations represent coded information.
5. The sound, image, or message transmitted or received by means of telecommunications.
Notably out of the ordinary: a signal feat; a signal event.
v. sig·naled, sig·nal·ing, sig·nals or sig·nalled or sig·nal·ling
1. To make a signal to: I signaled the driver to proceed.
2. To relate or make known by signals: They have signaled their willingness to negotiate.
3. To cause an effect in (a cell) by the activation of a receptor, as by a neurotransmitter or hormone.
To make a signal or signals.

[Middle English, from Old French, from Medieval Latin signāle, from neuter of Late Latin signālis, of a sign, from Latin signum, sign; see sign.]

sig′nal·er, sig′nal·ler n.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.signaler - someone who communicates by signalssignaler - someone who communicates by signals
communicator - a person who communicates with others
signalman - a railroad employee in charge of signals and point in a railroad yard
bell ringer, ringer, toller - a person who rings church bells (as for summoning the congregation)
whistler - someone who makes a loud high sound
References in classic literature ?
At that moment, on the road from the town on which signalers had been posted, two men appeared on horse back.
Selon un communique de la radio algerienne, 1020 appels emanent de citoyens ayant valorise cette louable initiative alors que 14 autres appels ont ete effectues pour signaler des feux de forets.
Pres de 600 jardins d'enfants anarchiques ont ete fermes au cours de l'annee 2016 et debut 2017, a declare samedi 25 mars 2017, la ministre de la Femme, de la Famille et de l'Enfance Neziha Laabidi, soulignant a ce propos l'importance de signaler ces etablissements illegaux.
Il convient de signaler que la federation generale du transport, relevant de l'UGTT a annonce, le 15 janvier 2014, que la greve de la SNTRI prevue, initialement, du 20 et 22 janvier 2014 a ete reportee au 28, 29 et 30 janvier 2014, en raison des interventions menees par le ministere des affaires sociales.