signals
signals — noun
- signalssingular
- signalsesplural
1. A deliberate action, movement, sound, or object used to send information, give a
A deliberate action, movement, sound, or object used to send information, give a warning, or tell someone what to do.
Andrei raised his hand as a signal to get the teacher's attention.
signal + to-infinitive shows purpose
The lifeguard blew a whistle as a signal for everyone to leave the water.
signal + for + noun + to-infinitive
Sofia saw the smoke from the hilltop and knew it was a signal for help.
The referee gave a clear signal that the match was about to begin.
文法句型
signal + of + noun
signal + to-infinitive
signal + that-clause
用法筆記
Often used with verbs like give, send, make, or flash. The preposition for introduces the recipient or purpose.
常見錯誤
2. A light on a vehicle that flashes to show that the driver intends to turn left o
A light on a vehicle that flashes to show that the driver intends to turn left or right.
Omar checked his mirrors and put on his left turn signal before changing lanes.
turn signal as noun phrase for vehicle light
The car in front of Jenna stopped suddenly without using any turn signals at all.
Kabir's turn signal was broken, so he used hand gestures to indicate a right turn.
It is against the law to change lanes without activating your turn signal first.
文法句型
turn signal
indicator
用法筆記
Also called an indicator in British English. In everyday conversation, Americans often say blinker.
常見錯誤
3. A flow of energy in the form of waves or pulses that transmits sound, images, or
A flow of energy in the form of waves or pulses that transmits sound, images, or data between a sender and a receiver.
The mountain blocked the radio signal, so Dario could not call for help.
signal + verb: can be blocked, lost, or received
Sofia adjusted the antenna on the roof to get a stronger television signal.
Wi-Fi signals can pass through walls but become weaker over long distances.
The satellite sends a signal back to Earth carrying weather information every minute.
- transmission
focuses on the act of sending, not the waves themselves
- wave
technical term for the physical pattern in which a signal travels
文法句型
radio signal
signal strength
signal + is + adjective
用法筆記
Frequently modified by adjectives describing the type of transmission: radio signal, digital signal, Wi-Fi signal. Signal strength describes how well the signal can be received.
常見錯誤
4. An event, condition, or piece of evidence that reveals the existence of somethin
An event, condition, or piece of evidence that reveals the existence of something or makes a future event seem likely.
Rising food prices are often a signal of broader economic problems ahead.
signal + of + noun phrase showing what is indicated
The early arrival of migrating birds is a clear signal that spring has begun.
Min took the manager's silence as a signal that the proposal had been rejected.
Falling stock prices sent a worrying signal to investors around the world.
- sign
more general and can be natural; does not imply a deliberate message
- indication
more formal; focuses on what can be inferred from evidence
- hint
a subtle signal; less direct and often incomplete
文法句型
signal + of + noun
signal + that-clause
用法筆記
This sense is often used with verbs like send, receive, take something as, or be a. Unlike noun sense 1, this signal is not a deliberate act — it is something that can be interpreted from events.
常見錯誤
❌ 'Dark clouds are a sign of rain.' — This is correct as a natural indication, but 'signal' in this sense can be used similarly. The difference is that 'sign' is neutral, while 'signal' often implies something interpreted by people.
5. A set of lights or mechanical signs placed on roads or railways to tell drivers
A set of lights or mechanical signs placed on roads or railways to tell drivers or trains when to stop, go, or slow down.
Jason stopped at the traffic signal and waited for the light to turn green.
traffic signal as noun phrase
The railway signals showed a red light, so the train reduced speed immediately.
Sade waited at the pedestrian crossing until the traffic signal flashed the walk sign.
The city installed new traffic signals at every intersection along the main road.
- traffic light
the common everyday term, especially in American English
- stoplight
informal American English term
- lights
shortened everyday form: 'turn left at the lights'
文法句型
traffic signals
railway signals
用法筆記
In American English, traffic lights and stoplights are more common in casual speech. Traffic signal is the formal term used in official documents and road regulations.
常見錯誤
signals — verb
- signalspresent simple I / you / we / they
- signalses3rd person singular
- signalsing-ing form
- signalsedpast simple
1. To use a gesture, sound, flash, or other action to convey information or give an
To use a gesture, sound, flash, or other action to convey information or give an instruction to someone.
The coach signalled to the players that it was time to switch positions.
signal + to + noun + that-clause
Ilan signalled for a taxi by raising his arm above his head at the curb.
signal + for + noun (request)
The ship signalled its location by sending three short flashes of light.
Liam blew his whistle and signalled the runners to cross the finish line.
文法句型
signal + to + noun
signal + that-clause
signal + noun
signal + for + noun + to-infinitive
用法筆記
When the receiver is mentioned, use signal to + person. When the purpose is stated, use signal for + thing. The transitive form takes a direct object (signal an order, signal a turn).
常見錯誤
2. To make it known, by words or actions, that you intend to do something or that a
To make it known, by words or actions, that you intend to do something or that a particular change is coming.
The company signalled that it planned to hire three hundred new workers next year.
signal + that-clause for corporate intention
Soraya signalled her willingness to lead the project by volunteering for the role.
signal + noun phrase showing readiness
The prime minister's speech signalled a major shift in the country's foreign policy.
Jenna put on her coat and grabbed her bag, signalling she was ready to leave.
- announce
more direct and explicit; always involves words, not actions
- indicate
suggests something is shown indirectly rather than stated openly
- demonstrate
emphasises showing through action or evidence
文法句型
signal + that-clause
signal + noun
signal + to-infinitive
用法筆記
Frequently used in business and political contexts. Unlike verb sense 1, this sense does not require a physical gesture — the signalling can be done through statements, decisions, or visible changes in behaviour.
常見錯誤
signals — adjective
- signalspositive
- more signalscomparative
- most signalssuperlative
1. Very noticeable and important; standing out from what is ordinary or expected.
Very noticeable and important; standing out from what is ordinary or expected.
Winning the award was a signal honour for the young scientist and her team.
attributive use before abstract nouns like honour, achievement, failure
The book marked a signal achievement in the field of modern architecture.
The army suffered a signal defeat that changed the course of the war entirely.
There has been a signal lack of progress on the issue since the negotiations began.
- notable
the closest synonym; less formal and more versatile
- remarkable
emphasises that something is worth noticing because it is unusual
- outstanding
emphasises excellence or superiority
- ordinary
unremarkable; not standing out
- unremarkable
not notable; lacking distinction
文法句型
signal + noun
用法筆記
Used only before a noun (attributive). It appears mostly in formal writing and with abstract nouns such as honour, achievement, failure, triumph, or lack. Do not use in casual conversation.