signal noun

1 sign/action/sound that sends a message

ADJ. clear, unmistakable | agreed, pre-arranged | conflicting, confusing, contradictory, mixed | wrong Laughing when you should be crying sends out the wrong signals to people. | alarm, danger, distress, warning | hand, non-verbal, semaphore, smoke, verbal, visual

VERB + SIGNAL arrange He had arranged a signal for the band to begin. | give (sb), make, send (out) When I give the signal, run! | interpret (sth as), read, see sth as The remark was seen as a signal that their government was ready to return to the peace talks. | pick up, respond to Interviewers quickly learn to pick up non-verbal signals. | act as The insect's bright colours act as warning signals to its predators.

SIGNAL + VERB come from sth trying to read the signals coming from the patient | indicate sth the signals that can indicate danger

PREP. at/on a ~ At a pre-arranged signal, everyone started cheering. | ~ for She made a signal for the car to stop. | ~ from/to Wait for the signal from the leader of your group.

2 set of lights for drivers

ADJ. railway, traffic

VERB + SIGNAL operate

SIGNAL + VERB be (on) red/green The traffic signals were on red. | fail

SIGNAL + NOUN box | failure

3 series of radio waves, chemical messages, etc.

ADJ. faint, weak | strong | high-frequency, low-frequency | acoustic, analogue, audio, chemical, digital, electrical, electronic, light, radar, radio, sonar, sound, television/TV, video, wireless

VERB + SIGNAL carry, pass The nerves carry these signals to the brain. | convert (sth into), scramble, unscramble The signal is scrambled into code before it is sent. | emit, generate, send, transmit | detect, pick up, receive, respond to This equipment can detect very low frequency signals.

SIGNAL + VERB travel A light signal can travel well over 16km before it halves in intensity. | fade

PREP. ~ from a faint signal from the satellite | ~ to