communication - something that is communicated by or to or between people or groups

recording - signal encoding something (e.g., picture or sound) that has been recorded

phone number, telephone number, number - the number is used in calling a particular telephone; "he has an unlisted number"

starting signal, start - a signal to begin (as in a race); "the starting signal was a green light"; "the runners awaited the start"

storm signal - a signal announcing the approach of a storm especially one of marked violence

beam, radio beam - a signal transmitted along a narrow path; guides pilots in darkness or bad weather

ticktack - system of signalling by hand signs used by bookmakers at racetracks

time signal - a signal (especially electronic or by radio) indicating the precisely correct time

dog-ear - a corner of a page turned down to mark your place

animal communication - communication between animals (of the same species)

alarum, warning signal, alarm, alert - an automatic signal (usually a sound) warning of danger

distress call, distress signal - an internationally recognized signal sent out by a ship or plane indicating that help is needed

all clear - a signal (usually a siren) that danger is over

bugle call - a signal broadcast by the sound of a bugle

curfew - a signal (usually a bell) announcing the start of curfew restrictions

retreat - (military) a signal to begin a withdrawal from a dangerous position

drumbeat - (military) the beating of a drum as a signal for lowering the flag at sundown

radiotelegraphic signal, telegraphic signal - a signal transmitted by telegraphy

whistle, whistling - the act of signalling (e.g., summoning) by whistling or blowing a whistle; "the whistle signalled the end of the game"

high sign - a silent signal of warning or recognition; "she started to speak but he gave her the high sign"

symbol - an arbitrary sign (written or printed) that has acquired a conventional significance

visual signal - a signal that involves visual communication

indicator - a signal for attracting attention

electronic signal - a signal generated by electronic means

radio beacon - a characteristic signal emitted by a transmitter used for navigation

input, input signal - signal going into an electronic system

output signal, output - signal that comes out of an electronic system