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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.




the action of generating or transmitting signals


, (US) signaling
References in periodicals archive ?
Contract notice: Supply of Crossing control signalling equipment
The course also covers subjects, such as teletraffic engineering and signalling, that are not only relevant to conventional telephone networks but also Voice over IP (VoIP) services.
com/reports/c39120) has announced the addition of E-Learning Course: C7 Signalling Systems to their offering.
B) has received contracts from Metronet for the supply of rolling stock, signalling, maintenance and project management for the modernisation of London's Underground system.
Full Support for AAL2 and AAL5 Creates a Completely Scalable and Flexible Signalling Solution for Network Designers
H&J), has begun delivery of a new version of its industry-leading Soft-ATM Signalling Software Subsystem (SSS).
last Friday announced that it has released and shipped the first commercially available source code software product supporting Frame Relay SVC/PVC Signalling.