dilate

verb

di·​late ˈdī-ˌlāt  dī-ˈlāt 

dilated; dilating

intransitive verb

1

a

: to become enlarged or widened

Kim's eyes dilated while the outdoor stadium rocked in celebration.

—Ralph Wiley

… arterioles continually dilate and constrict.

—Janet Raloff

also : to display or become affected by expansion or widening of a body part

The expectant mother was dilating slowly. [=The expectant mother's cervix was dilating slowly.]

b

: to become expanded in extent

Understandably, a tendency to philosophize dilated with old age.

—Anthony Powell

Time dilates when you mentally hop continents.

—Bret Wallach

2

: to comment at length : discourse

—usually used with on or upon

It's no small irony that a man who made a career out of dilating on failure should have ended up a success.

—James Atlas

He dwells and dilates upon every highlight and lowlight …

—The New Yorker

transitive verb

1

a

: to enlarge, widen, or cause to expand

Nitric oxide is a potent vasodilator that increases blood flow by dilating blood vessels.

—Ruth MacPete

Inhalers, the standard treatment for asthma, relieve wheezing by delivering an agent that dilates the bronchioles …

—Tony Dajer

Cocaine … increases the heart rate, raises the blood pressure and, in large doses, increases the body temperature and dilates the pupils of the eyes.

—Craif Van Dyke and Robert Byck

b

: to expand in extent

dilate our cultural knowledge

Like millions of other urban youths in the 1960s, Tian got a chance to dilate his horizons when he was sent into the countryside during the Cultural Revolution to learn from the peasantry.

—Lawrence Chua

2

archaic : to describe or set forth at length or in detail

Do me the favor to dilate at full / What hath befallen of them …

—William Shakespeare

dilatability

(ˌ)dī-ˌlā-tə-ˈbi-lə-tē 

noun

dilatable

dī-ˈlā-tə-bəl  ˈdī-ˌlā- 

adjective

dilator

dī-ˈlā-tər 

ˈdī-ˌlā-

noun

Synonyms

• develop
• expand
• supplement
• enlarge (on or upon)
• flesh (out)
• elaborate (on)

Choose the Right Synonym for dilate

expand, amplify, swell, distend, inflate, dilate mean to increase in size or volume.

expand may apply regardless of the manner of increase (such as growth, unfolding, addition of parts).

a business that expands every year

amplify implies the extension or enlargement of something inadequate.

amplify the statement with details

swell implies gradual expansion beyond a thing's original or normal limits.

the bureaucracy swelled to unmanageable proportions

distend implies outward extension caused by pressure from within.

a distended abdomen

inflate implies expanding by introduction of air or something insubstantial and suggests a vulnerability to sudden collapse.

an inflated ego

dilate applies especially to expansion of circumference.

dilated pupils

Examples of dilate in a Sentence

The drug causes the blood vessels to dilate.

During labor, a woman's cervix will dilate to about 10 centimeters.

The drug dilates the blood vessels.

Recent Examples on the Web

In order to find out if this was the case, doctors needed to dilate his pupils to check. —Jack Beresford, MSNBC Newsweek, 28 June 2025

Erections rely on the bioavailability of nitric oxide and the ability of blood vessels to dilate efficiently. —Ximena Araya-Fischel, Forbes.com, 26 June 2025

Our interview, however, was just two days earlier, and his surrogate was already three centimeters dilated! —Lauren Brown West-Rosenthal, Parents, 12 June 2025

Hissing Another common sign, according to Smith, is hissing at you while their pupils are dilated. —Mark Weinstein, MSNBC Newsweek, 27 Apr. 2025

Word History

Etymology

Middle English, from Middle French dilater, from Latin dilatare, literally, to spread wide, from dis- + latus wide — more at latitude

First Known Use

14th century, in the meaning defined at transitive sense 2

Phrases Containing dilate

• dilate on/upon

Rhymes for dilate

• abate
• airfreight
• await
• baseplate
• berate
• birthdate
• birthrate
• bookplate
• borate
• breastplate
• bromate
• casemate

Kids Definition

dilate

verb

di·​late dī-ˈlāt  ˈdī-ˌlāt 

dilated; dilating

: to make or grow larger or wider

lungs dilated with air

Medical Definition

dilate

verb

di·​late dī-ˈlāt  ˈdī-ˌ 

dilated; dilating

transitive verb

: to enlarge, widen, or cause to expand

dilate his pupils with atropine

the drug dilates peripheral arteries

intransitive verb

: to become enlarged, expanded, or widened

the cervix was dilating

the pupils dilated