A classic problem of English usage. Unfortunately, the commonest advice usually simplifies the matter as follows:
Affect is a verb meaning “to change or to make a difference”; effect is a noun meaning “the result of a change.”
In fact, both affect and effect can be either a verb or a noun, and there is a much wider range of meaning than indicated above.
to change, to make a difference, to have a material effect
- The weather will surely affect my plans this weekend.
- The hole in the bucket deleteriously affects its utility.
to impress, to touch, to move, to have an emotional effect
- His severe mien affected my perception of his character.
- The soprano’s performance affected my mood for a week.
to pretend, to feign, to assume a display for appearance’s sake, to prefer (for appearance’s sake)
- He affected surprise, even though he had learned of the news beforehand.
- So persuasively did she affect a certain country folksiness that no one ever did guess that she was a multimillionaire manufacturing magnate.
- Punk rockers will often affect a countercultural attitude so as to appear authentic to their fans, whereas the production and sale of their products belie such pretensions.
a disposition, feeling, temper, affection
- A sombre affect pervaded the funeral parlor.
- The spring rain suggested to the poet an affect for her verse.
- His affect was phlegmatic and elusive.
an affectation (rarer)
- She assumed an affect of indifference [to avoid showing how much she really cared].
to cause, to bring about, to accomplish or to obtain an effect, to bring to completion [perfective]
- The signing of the law effected the long-awaited policy.
- By no means can impossible goals be effected.
to cause, to carry out, to put into effect, to inaugurate [progressive]
- One must pay the insurance premium to effect coverage.
- Step by step, we can effect the changes we seek.
a state or fact of being operative or in force
- Although no longer in effect, the law still holds sway in the civic consciousness.
- This toilet is out of order with immediate effect.
- The insurance certificate takes effect on the first of the month.
a result, a consequence, a thing accomplished, a phenomenon
- Although the law has been repealed, it still retains an effect in the civic consciousness.
- Wind is an effect of the mixing of air masses of different temperatures.
- The team hopes that the effect of their rigorous training shall be victory and glory.
- The Pied Piper effect suggests that if we can persuade the chair, the committee will follow.
a (desirable) purpose, a (pleasing or remarkable) gestalt [related to previous sense]; often pl.
- Mozart deploys the trombones to great effect in his Requiem.
- Confetti at a party often has a disappointing effect.
- The impressionistic color effects of painters like Monet helped give their movement its name.