A signal is a gesture or message that people use to communicate with each other. The wave you give a good friend to call her over from across the room and the impulse that transmits your voice through the telephone to your mother are both signals.

In the course of a single day, you probably send and receive thousands of different signals. When you want to cross the street, you wait for the green light — a signal that it's safe to cross. If you're in a relationship and you're not sure whether you like the person you're dating, you could be sending mixed signals — first acting like you're interested, and then acting uninterested. If your date finally gets tired of your mixed signals while you're at a restaurant, you'll need to signal to your server that it's time for the check.

Definitions of signal

n any action or gesture that encodes a message

signals from the boat suddenly stopped”
sign, signaling
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a signal that encodes something (e.g., picture or sound) that has been recorded
number, phone number, telephone number
the number is used in calling a particular telephone
start, starting signal
a signal to begin (as in a race)
storm signal
a signal announcing the approach of a storm (particularly a storm of marked violence)
beam, radio beam
a signal transmitted along a narrow path; guides airplane pilots in darkness or bad weather
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
a corner of a page turned down to mark your place
animal communication
communication between animals (of the same species)
alarm, alarum, alert, warning signal
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
a signal (usually a bell) announcing the start of curfew restrictions
(military) a signal to begin a withdrawal from a dangerous position
(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
high sign
a silent signal of warning or recognition
an arbitrary sign (written or printed) that has acquired a conventional significance
visual signal
a signal that involves visual communication
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, output signal
signal that comes out of an electronic system
bologram, bolograph
record or recording made by a bolometer
the recording (column or paper strip) on which the constituents of a mixture are adsorbed in chromatography
the recording produced by an oscillograph
a recording of breathing made with a spirograph
a small explosive device that is placed on a railroad track and fires when a train runs over it; the sound of the explosion warns the engineer of danger ahead
stock symbol
the letters used to identify listed companies on the securities exchanges where they are traded
accolade, award, honor, honour, laurels
a tangible symbol signifying approval or distinction
storm cone
a canvas cone hoisted to warn of high winds
brand, mark, stain, stigma
a symbol of disgrace or infamy
item, token
an individual instance of a type of symbol
all of the tokens of the same symbol
birdcall, birdsong, call, song
the characteristic sound produced by a bird
air alert
the warning signal that begins a period of preparation for an enemy air attack
burglar alarm
a loud warning signal produced by a burglar alarm
an internationally recognized distress signal in radio code
an internationally recognized distress signal via radiotelephone (from the French m'aider)
a bugle call that signals troops to return
lights-out, taps
(military) signal to turn the lights out
reveille, wake-up signal
(military) signal to wake up
(military) a bugle call signaling the lowering of the flag at sunset
a drumbeat or bugle call that signals the military to return to their quarters
dit, dot
the shorter of the two telegraphic signals used in Morse code
dah, dash
the longer of the two telegraphic signals used in Morse code
a symbol of inquisitiveness
number, numeral
a symbol used to represent a number
a system of symbols and symbolic representations
the Hindu phallic symbol of Siva
pound, pound sign
a symbol for a unit of currency (especially for the pound sterling in Great Britain)
printed symbol, written symbol
a written or printed symbol
dollar, dollar mark, dollar sign
a symbol of commercialism or greed
a graphic symbol consisting of 2 or more letters combined (usually your initials); printed on stationery or embroidered on clothing
impression, stamp
a symbol that is the result of printing or engraving
watch fire
a fire lighted at night as a signal
a visual warning signal
red light, warning light
a cautionary sign of danger
flare, flash
a burst of light used to communicate or illuminate
flag, signal flag
a rectangular piece of fabric used as a signalling device
the cloak as a symbol of authority
the Crown (or the reigning monarch) as the symbol of the power and authority of a monarchy
air sock, air-sleeve, drogue, sock, wind cone, wind sleeve, wind sock, windsock
a truncated cloth cone mounted on a mast; used (e.g., at airports) to show the direction of the wind
post, stake
a pole or stake set up to mark something (as the start or end of a race track)
point of reference, reference, reference point
an indicator that orients you generally
blinker, trafficator, turn indicator, turn signal
a blinking light on a motor vehicle that indicates the direction in which the vehicle is about to turn
worn around arm as identification or to indicate mourning
rocket, skyrocket
propels bright light high in the sky, or used to propel a lifesaving line or harpoon
radar echo
an electronic signal that has been reflected back to the radar antenna; contains information about the location and distance of the reflecting object
racon, radar beacon
a device that, on receiving radar signals, transmits coded signals in response to help navigators determine their position
beacon, beacon fire
a fire (usually on a hill or tower) that can be seen from a distance
the output of a computer in printed form
read-out, readout
the output of a computer in readable form
fire alarm
a shout or bell to warn that fire has broken out
foghorn, fogsignal
a loud low warning signal that can be heard by fogbound ships
a noise made by the driver of an automobile to give warning;
red flag
a flag that serves as a warning signal
a warning signal that is a loud wailing sound
alarm bell, tocsin
the sound of an alarm (usually a bell)
brake light, stoplight
a red light on the rear of a motor vehicle that signals when the brakes are applied to slow or stop
barber's pole
striped pole outside a barbershop
a rod carried as a symbol
(computer science) a graphic symbol (usually a simple picture) that denotes a program or a command or a data file or a concept in a graphical user interface
mark, marker, marking
a distinguishing symbol
a symbol that establishes the identity of the one bearing it
a symbol (like x or y) that is used in mathematical or logical expressions to represent a variable quantity
Type of:
something that is communicated by or to or between people or groups

n any incitement to action

“he awaited the signal to start”
“the victory was a signal for wild celebration”
Type of:
incitation, incitement, provocation
something that incites or provokes; a means of arousing or stirring to action

n an electric quantity (voltage or current or field strength) whose modulation represents coded information about the source from which it comes

a signal that temporarily stops the execution of a program so that another procedure can be carried out
Type of:
electrical energy, electricity
energy made available by the flow of electric charge through a conductor

adj notably out of the ordinary

“the year saw one signal triumph for the Labour party”
making a strong or vivid impression

v communicate by means of an action, gesture, or sound

“The diner signaled the waiters to bring the menu”
sign, signalise, signalize
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signal by or as if by a flag or light waved according to a code
send signals by or as if by semaphore
signal by means of a mirror and the using the sun's rays
communicate or signal with a flag
give a signal by whistling
Type of:
communicate, intercommunicate
transmit thoughts or feelings

v be a signal for or a symptom of

“The economic indicators signal that the euro is undervalued”
bespeak, betoken, indicate, point
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augur, auspicate, betoken, bode, forecast, foreshadow, foretell, omen, portend, predict, prefigure, presage, prognosticate
indicate by signs
designate as if by a mark
to be a menacing indication of something:"The clouds threaten rain"
indicate by marking trees with blazes
indicate the dimensions on
mark with a signpost, as of a path
distinguish, signalise, signalize
make conspicuous or noteworthy
mark with a buoy
foretell by divine inspiration
Type of:
let something be known

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