dilate
Americanverb (used with object)
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to make wider or larger; cause to expand.
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Archaic. to describe or develop at length.
verb (used without object)
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to spread out; expand.
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to speak or write at length; expatiate (often followed by on orupon ).
verb
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to expand or cause to expand; make or become wider or larger
the pupil of the eye dilates in the dark
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(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
As a result, blood flow to that area increases dramatically as blood vessels dilate, causing pain and swelling.
From National Geographic • Feb. 21, 2024
Longer-term use of a catheter would only be needed if doctors were unable to sufficiently dilate the urethra.
From New York Times • Feb. 12, 2024
During the exam, pictures are taken of the backs of the eyes without the need to dilate them, and AI is used to provide an immediate result.
From Science Daily • Jan. 13, 2024
Of all earthly pleasures, Laila’s favorite was lying next to Aziza, her baby’s face so close that she could watch her big pupils dilate and shrink.
From "A Thousand Splendid Suns" by Khaled Hosseini
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.
