[ im-pak-shuh n ]
/ ɪmˈpæk ʃən /


an act or instance of impacting.
the state of being impacted; close fixation.
Dentistry. the condition in which a tooth is impacted.

Origin of impaction

1730–40; < Late Latin impāctiōn- (stem of impāctiō), equivalent to Latin impāct(us), past participle of impingere (see impacted) + -iōn- -ion Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for impaction

Word Origin and History for impaction



1739, from Latin impactionem (nominative impactio) "a striking against," noun of action from past participle stem of impingere (see impinge).

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for impaction


[ ĭm-păkshən ]


The process or condition of being impacted.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.