[dahy-leyt, di-, dahy-leyt]

verb (used with object), di·lat·ed, di·lat·ing.

to make wider or larger; cause to expand.
Archaic. to describe or develop at length.

verb (used without object), di·lat·ed, di·lat·ing.

to spread out; expand.
to speak or write at length; expatiate (often followed by on or upon).

Origin of dilate

1350–1400; Middle English dilaten < Middle French dilater, Latin dīlātāre to spread out, equivalent to dī- di-2 + lāt(us) broad + -āre infinitive suffix
Related formsdi·lat·a·bil·i·ty, noundi·lat·a·ble, adjectivenon·di·lat·a·bil·i·ty, nounnon·di·lat·a·ble, adjectiveo·ver·di·late, verb, o·ver·di·lat·ed, o·ver·di·lat·ing.re·di·late, verb, re·di·lat·ed, re·di·lat·ing.self-di·lat·ed, adjectivesub·di·lat·ed, adjectiveun·di·lat·a·ble, adjectiveun·di·lat·ed, adjectiveun·di·lat·ing, adjective
Can be confuseddilate dilute

Synonyms for dilate

1. See expand.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for dilate

Historical Examples of dilate

British Dictionary definitions for dilate



to expand or cause to expand; make or become wider or largerthe pupil of the eye dilates in the dark
(intr; often foll by on or upon) to speak or write at length; expand or enlarge
Derived Formsdilatable, adjectivedilatability or dilatableness, noundilation or dilatation (ˌdaɪləˈteɪʃən, ˌdɪ-), noundilatational, adjectivedilative (daɪˈleɪtɪv, dɪ-), adjective

Word Origin for dilate

C14: from Latin dīlātāre to spread out, amplify, from dis- apart + lātus wide
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

Word Origin and History for dilate

late 14c., from Old French dilater, from Late Latin dilatare "make wider, enlarge," from dis- "apart" (see dis-) + latus "wide" (see latitude). Related: Dilated; dilating.

Online Etymology Dictionary, © 2010 Douglas Harper

dilate in Medicine


[dī-lāt, dīlāt′]


To make or become wider or larger.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.