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¹signal

noun sig·nal \ˈsig-n^əl\

: an event or act which shows that something exists or that gives information about something

: something (such as a sound, a movement of part of the body, or an object) that gives information about something or that tells someone to do something

: a piece of equipment with colored lights that is used on railways and roads to tell people when to go, to slow down, or to stop

Full Definition of SIGNAL

: sign, indication

a : an act, event, or watchword that has been agreed on as the occasion of concerted action

b : something that incites to action

: something (as a sound, gesture, or object) that conveys notice or warning

a : an object used to transmit or convey information beyond the range of human voice

b : the sound or image conveyed in telegraphy, telephony, radio, radar, or television

c : a detectable physical quantity or impulse (as a voltage, current, or magnetic field strength) by which messages or information can be transmitted

See signal defined for English-language learners

See signal defined for kids

Origin of SIGNAL

Middle English, from Medieval Latin signale, from Late Latin, neuter of signalis of a sign, from Latin signum

First Known Use: 14th century

Related to SIGNAL

Synonyms: flag, tocsin

²signal

verb

: to be a sign of (something) : to show the existence of (something)

: to make a sound or motion that tells someone something

sig·naled or sig·nalledsig·nal·ing or sig·nal·ling \-nə-liŋ\

Full Definition of SIGNAL

transitive verb

: to notify by a signal <signal the fleet to turn back>

a : to communicate or indicate by or as if by signals <signaled the end of an era>

b : to constitute a characteristic feature of (a meaningful linguistic form)

intransitive verb

: to make or send a signal

— sig·nal·er or sig·nal·ler noun

See signal defined for English-language learners

First Known Use of SIGNAL

1805

Related to SIGNAL

Synonyms: beckon, flag, gesture, motion, wave

³signal

adjective

: very important or great

Full Definition of SIGNAL

: distinguished from the ordinary : notable <a signal achievement>

See signal defined for English-language learners

Origin of SIGNAL

modification of French signalé, past participle of signaler to distinguish, from Old Italian segnalare to signal, distinguish, from segnale signal, from Medieval Latin signale

First Known Use: 1627

Related to SIGNAL

Synonyms: astral, bright, distinguished, illustrious, luminous, noble, notable, noteworthy, outstanding, preeminent, prestigious, redoubtable, eminent, star, superior

SIGNAL Defined for Kids

¹signal

noun sig·nal \ˈsig-n^əl\

Definition of SIGNAL for Kids

: a sign, event, or word that serves to start some action <… the manager gave the signal for the curtain to go down, and the audience … cheered. — Richard and Florence Atwater, Mr. Popper's Penguins>

: a sound, a movement of part of the body, or an object that gives warning or a command <The police officer made a signal with his hand.> <a traffic signal>

: a radio wave that transmits a message or effect (as in radio or television)

Word Root of SIGNAL

The Latin word signum, meaning “mark” or “indication,” gives us the root sign. Words from the Latin signum have something to do with marks, signs, or indications. A sign is a move of the hand that indicates something to others. To designate is to mark someone or something for a special purpose. A signal is an indication that an action should begin.