signal
signal — noun
1. a gesture, action, or sound used to pass information to someone, often to give i
a gesture, action, or sound used to pass information to someone, often to give instructions or a warning
Rin raised her hand — a clear signal that she had found the trail.
signal + that-clause for giving information
The coach blew his whistle as a signal for the players to gather around.
signal + for + noun + to-infinitive
Dario gave the waiter a quick signal by holding up two fingers.
A flashing light on the dashboard is a signal that the engine needs a mechanic.
- gesture
focuses on the body movement, not the message it carries
- cue
a signal that tells someone to start doing something, especially in a performance or routine
- indication
a more general word that can be intentional or unintentional
文法句型
a signal + that-clause
a signal + for + noun + to-infinitive
give (somebody) a signal
用法筆記
Commonly followed by a that-clause (a signal that…) or a to-infinitive (a signal to stop). Unlike sign, a signal is always deliberately made by a person or device.
常見錯誤
2. one of the flashing lights on a car or other vehicle that shows which direction
one of the flashing lights on a car or other vehicle that shows which direction the driver plans to turn
Sofia flicked on her left turn signal well before reaching the junction.
use / activate a turn signal
William checked his mirrors and activated his turn signal before changing lanes on the highway.
The driver behind honked because Nila had forgotten to use her signal when turning right.
A broken turn signal can get you a fine in most countries around the world.
文法句型
use/put on a turn signal
用法筆記
In British English, 'indicator' is more common than 'turn signal'. Often shortened to just 'signal' in informal driving contexts ('Did you use your signal?').
常見錯誤
3. waves of energy sent through the air to transmit sounds, pictures, or other info
waves of energy sent through the air to transmit sounds, pictures, or other information to electronic devices like televisions, radios, and mobile phones
The television picture went fuzzy when the radio signal weakened during the storm.
signal + weakens / loses strength
Élise climbed the hill with her phone held high, searching for a mobile signal.
mobile signal / phone signal
The satellite signal was strong enough to broadcast the match live across five continents.
Sivan adjusted the roof antenna to improve the radio signal from the station.
文法句型
signal + [adjective]
lose / pick up a signal
用法筆記
Subject is usually a type of signal (radio, TV, mobile, satellite). Frequently pairs with verbs like lose, pick up, strengthen, weaken, and block.
4. any observable fact or development that indicates another thing is present, happ
any observable fact or development that indicates another thing is present, happening, or about to happen
Rising prices are often a signal that the economy is growing faster than expected.
a signal + that-clause (indication)
Femi took his colleague's silence as a signal that nobody supported the proposal.
take something as a signal
The company's decision to hire new staff is a strong signal of growth.
Early flowers in February are a hopeful signal that spring is arriving sooner this year.
文法句型
a signal + that-clause
a signal + of + noun
用法筆記
Distinguish from sense 1: sense 1 refers to a deliberate communication (e.g. waving someone over), while sense 4 describes something that naturally indicates a condition or likelihood, often without anyone intending to send it.
常見錯誤
5. a device with coloured lights positioned next to a road or railway track to regu
a device with coloured lights positioned next to a road or railway track to regulate the flow of cars or trains
The train slowed down as the railway signal ahead changed from green to red.
railway signal
Omar waited at the traffic signal for the light to turn green before crossing.
traffic signal
Trains were held outside the station because red signals blocked the track.
The city installed new pedestrian signals at the busy intersection near the school.
- traffic light
the common everyday term for road signals
- stoplight
American informal term for a road traffic light
- lights
informal shortening ('turn left at the lights')
用法筆記
In road contexts, 'traffic light' is more common in everyday speech, while 'traffic signal' is the formal term used in official notices and regulations. On railways, 'signal' is the standard term.
常見錯誤
signal — verb
1. to use a gesture, light, or sound to send information or instructions to another
to use a gesture, light, or sound to send information or instructions to another person or group
The lifeguard signalled to the swimmers to come back to the shore immediately.
signal + to + somebody + to-infinitive
Mathieu signalled the taxi by raising his arm above his head on the busy street.
signal + noun (transitive, mainly British)
The referee signalled that the goal was valid by pointing to the centre.
Rin signalled for help by flashing her torch three times into the dark sky.
文法句型
signal + to + somebody + to-infinitive
signal + that-clause
signal + for + noun
signal + noun
用法筆記
Can be transitive ('signal somebody') or intransitive ('signal to somebody'). The transitive use is more common in British English; American English prefers 'signal to somebody' or 'signal that…'.
常見錯誤
2. to make clear to others that you plan to take a particular action or are prepare
to make clear to others that you plan to take a particular action or are prepared for something
The company has signalled its intention to cut costs by closing three factories overseas.
signal + intention/readiness + to-infinitive
Chidi signalled he was ready to begin by standing up and walking to the screen.
signal + that-clause (intention)
By taking on extra work, Omar signalled his willingness to take more responsibility.
The government is signalling to investors that the tax rules will stay unchanged.
- indicate
broader; can be unintentional. 'Signal' implies a deliberate message
- announce
more direct and formal; involves a clear statement rather than an implied message
- communicate
general term for sharing information by any means
文法句型
signal + that-clause
signal + intention/readiness/willingness + to-infinitive
用法筆記
This sense is more abstract than sense 1 — it is about conveying an intention or message through decisions or policies rather than through physical gestures. Common in business and political contexts.
常見錯誤
signal — adjective
1. standing out from the ordinary because of great importance, quality, or effect —
standing out from the ordinary because of great importance, quality, or effect — used only before a noun
The discovery of insulin was a signal achievement in the history of medicine.
signal + achievement/success (formal, before noun)
There has been a signal lack of progress in the peace talks recently.
signal + lack of + noun (formal contrastive pattern)
Professor Hsu's research on early childhood education represents a signal contribution to the field.
The team's victory was a signal success, especially after losing their best player to injury.
- notable
less formal; can be used after a linking verb ('was notable')
- remarkable
similar in strength but can follow a linking verb
- striking
emphasises visual or immediate impact
- exceptional
suggests something is much better than average
- ordinary
the opposite of standing out; unremarkable
- insignificant
the opposite of important or meaningful
文法句型
signal + noun (before a noun, not after a linking verb)
用法筆記
Nearly always appears before a noun (attributive position). It is never used after a linking verb like be or seem. This is a formal word found in academic and journalistic writing, not in everyday conversation.