dilate
Americanverb (used with object)
-
to make wider or larger; cause to expand.
-
Archaic. to describe or develop at length.
verb (used without object)
-
to spread out; expand.
-
to speak or write at length; expatiate (often followed by on orupon ).
verb
-
to expand or cause to expand; make or become wider or larger
the pupil of the eye dilates in the dark
-
(intr; often foll by on or upon) to speak or write at length; expand or enlarge
Related Words
See expand.
Other Word Forms
- dilatability noun
- dilatable adjective
- dilatational adjective
- dilation noun
- dilative adjective
- nondilatability noun
- nondilatable adjective
- overdilate verb
- redilate verb
- self-dilated adjective
- subdilated adjective
- undilatable adjective
- undilated adjective
- undilating adjective
Etymology
Origin of dilate
First recorded in 1350–1400; Middle English dilaten, from Middle French dilater, “to comment at length, enlarge,” from Latin dīlātāre “to spread out, widen,” equivalent to dī- di- 2 + lāt(us) “wide” + -āre infinitive suffix
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Atropine eye drops are typically used to dilate the pupil before eye exams.
From The Wall Street Journal • Dec. 28, 2025
However, in their new study published in the peer-reviewed journal Attention, Perception & Psychophysics, the researchers reported that a person's pupils also dilate when they are concentrating on tasks.
From Science Daily • Apr. 22, 2024
Although it is not an ordinary high blood pressure medicine, it can dilate blood vessels.
From Seattle Times • Nov. 22, 2023
At regular concentrations of about 1 percent, atropine is used to dilate the pupil for eye exams.
From National Geographic • Nov. 1, 2023
The eyes seemed to expand and dilate until they filled the whole of Matthias’s vision.
From "Redwall" by Brian Jacques
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
