signal

An electrical or radio wave that carries sound, pictures, or other information.

• My phone has no signal here.
• The radio signal became stronger near the town.
• This device sends signals to a satellite.

Common phrases: phone signal, weak signal, radio signal

A sound, light, or movement that tells someone what to do.

• Wait until I give the signal.
• Her raised hand was a signal to stop.
• The runners listened for the starting signal.

How to use it: a signal to do something (The whistle was our signal to start running.)

Similar words: sign, cue

Common phrases: give a signal, signal to someone, start signal, warning signal

A light, picture, or other sign used to show who someone is or identify a ship or aircraft.

• The ship displayed its recognition signal.
• The pilot checked the signal before approaching the other aircraft.
• Each boat used a different signal to identify itself.

Similar words: identification sign

Common phrases: recognition signal, identification signal, signal flag

To use a movement, sound, or light to tell someone something.

• Please signal before you turn.
• She signalled to the waiter for the bill.
• He signaled that it was safe to cross.

How to use it: signal to someone to do something (She signalled to us to wait outside.); signal for something (He signalled for help from the window.); signal that… (The guard signalled that we could enter.)

Similar words: indicate, gesture

Common phrases: signal to someone, signal a turn, signal for help

Especially great, important, or successful.

• The project was a signal success.
• Her discovery remains a signal achievement in medicine.
• The award was a signal honour for the young scientist.

Similar words: remarkable, outstanding, notable

Common phrases: signal success, signal achievement, signal honour