aftereffect

UK: /ˈɑːftərɪˌfɛkt/

US: /ˈæftərɪˌfɛkt/

US: (af′tər i fekt′, äf′-)

WordReference Random House Learner's Dictionary of American English © 2025

af•ter•ef•fect /ˈæftərɪˌfɛkt/   n. [countable]

1. a delayed effect, as one that follows the stimulus that produced it:
   the aftereffects of the drug.

WordReference Random House Unabridged Dictionary of American English © 2025

af•ter•ef•fect  (af′tər i fekt′, äf′-), n. 

1. a delayed effect;
   an effect that follows at some interval after the stimulus that produces it.
2. Medicine a result appearing after the first effect due to an agent, usually a drug, has gone.

• after + effect 1810–20

Collins Concise English Dictionary © HarperCollins Publishers::

aftereffect / ˈɑːftərɪˌfɛkt/ noun

1. any result occurring some time after its cause
2. any delayed response to a stimulus or agent
   Compare side effect