Date: 1300-1400
Language: Old French
Origin: Latin effectus, past participle of efficere 'to cause to happen'


1 noun
ef‧fect1 S1 W1


[uncountable and countable] the way in which an event, action, or person changes someone or somethingCOLLOCATIONS COLLOCATIONS
have an effect (on somebody/something) big/major/profound/significant/dramatic effect bad/harmful/negative/damaging/detrimental/adverse effect beneficial/positive effect long-term effect feel the effect (of something) knock-on-effect British English (=an effect caused by the thing that happened before) cumulative effect (=the effect of many things happening one after another) the desired effect (=the effect you wanted) cause and effect (=one thing directly causing the other)
effect on
My parents' divorce had a big effect on me.
effect of
the harmful effects of modern farming practices
the long-term effects of the drug
I could feel the effects of the thin mountain air.
This ingredient also has the effect of making your skin look younger.
A system failure has a knock-on effect throughout the whole hotel.
the cumulative effect of human activities on the global environment
A much lower dose of the painkiller can still produce the desired effect.
In mental illness, there is a complex relationship between cause and effect.
greenhouse effect, side effect

put/bring something into effect

to make a plan or idea happen:
It won't be easy to put the changes into effect.

take effect

to start to produce results:
The morphine was starting to take effect and the pain eased.



take effect/come into effect

if a law, rule, or system takes effect or comes into effect, it officially starts

be in effect

if a law, rule, or system is in effect, it is being used now

with immediate effect/with effect from

formal starting to happen immediately, or from a particular date:
Hoskins is appointed manager, with immediate effect.

in effect

used when you are describing what you see as the real facts of a situation:
In effect, we'll be earning less than we were last year.

to good/great/no etc effect

used to show how successful an action is:
We tried to wake him, but to no effect.

to this/that/the effect

used when you are giving the general meaning of something, rather than the exact words:
Jim told me to go away, or words to that effect.
The letter said something to the effect that she was no longer needed.


[countable usually singular] an idea or feeling that an artist, speaker, book etc tries to make you think of or to feel
effect of
Turner's paintings give an effect of light.

for effect

if someone does something for effect, they do it in order to make people notice:
She paused for effect, then carried on speaking.

personal possessions


[plural] formal the things that someone owns [= belongings]:
Don's few personal effects were in a suitcase under the bed.


[countable usually plural]AMAPT an unusual or impressive sound or image that is artificially produced for a film, play, or radio programme

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