[ af-ter-i-fekt, ahf- ]
/ ˈæf tər ɪˌfɛkt, ˈɑf- /


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

Origin of aftereffect

First recorded in 1810–20; after + effect Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for aftereffect

/ (ˈɑːftərɪˌfɛkt) /


any result occurring some time after its cause
med any delayed response to a stimulus or agentCompare side effect
psychol any illusory sensation caused by a stimulus that has ceased
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012