dilate

UK: /dɪˈleɪt/, /daɪˈleɪt/

US: /daɪˈleɪt, ˈdaɪleɪt/

US: (dī lāt′, di-, dī′lāt)

Inflections of 'dilate' (v): (⇒ conjugate)

dilates

v 3rd person singular

dilating

v pres p

dilated

v past

dilated

v past p

WordReference Random House Learner's Dictionary of American English © 2026

di•late /daɪˈleɪt, ˈdaɪleɪt/   v., -lat•ed, -lat•ing. 

1. to (cause to) become wider, larger, or expanded: [no object]
   The cat's eyes dilated in the darkness.
   [~ + object]
   The medicine will dilate the blood vessels.

di•la•tion /daɪˈleɪʃən/  n. [uncountable] See -lat-².

WordReference Random House Unabridged Dictionary of American English © 2026

di•late  (dī lāt′, di-, dī′lāt), v., -lat•ed, -lat•ing. 
v.t. 

1. to make wider or larger;
   cause to expand.
2. [Archaic.] to describe or develop at length.

v.i. 

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

• Middle French dilater, Latin dīlātāre to spread out, equivalent. to dī- di-² + lāt(us) broad + -āre infinitive suffix
• Middle English dilaten 1350–1400

di•lat′a•bil′i•ty, n. 
di•lat′a•ble, adj. 
Synonyms

• 1. See expand. 

Collins Concise English Dictionary © HarperCollins Publishers::

dilate / daɪˈleɪt dɪ-/ verb

1. to expand or cause to expand; make or become wider or larger
2. (intr; often followed by on or upon) to speak or write at length; expand or enlarge

Etymology: 14th Century: from Latin dīlātāre to spread out, amplify, from dis- apart + lātus wide

diˈlatable adjective

diˌlataˈbility, diˈlatableness noun

diˈlation, dilatation / ˌdaɪləˈteɪʃən ˌdɪ-/ noun

dilative / daɪˈleɪtɪv dɪ-/ adjective