diffuse

1 of 2

adjective

dif·​fuse di-ˈfyüs How to pronounce diffuse (audio)
Synonyms of diffusenext
1
: being at once verbose and ill-organized
a diffuse report from the scene of the earthquake
2
: not concentrated or localized
diffuse lighting
diffuse sclerosis
diffusely adverb
diffuseness noun

diffuse

2 of 2

verb

dif·​fuse di-ˈfyüz How to pronounce diffuse (audio)
diffused; diffusing

transitive verb

1
a
: to pour out and permit or cause to spread freely
a drop of blue dye diffused in a glass of water
b
: extend, scatter
diffusing their ideas throughout the continent
c
: to spread thinly or wastefully
a government in which power is diffused
2
physics : to subject to diffusion (see diffusion sense 3)
especially : to break up and distribute (incident light) by reflection
put up a screen to diffuse the light

intransitive verb

1
: to spread out or become transmitted especially by contact
The civilization diffused westward.
2
: to undergo diffusion
heat from the radiator diffusing throughout the room
diffusible
di-ˈfyü-zə-bəl How to pronounce diffuse (audio)
adjective

Frequently Asked Questions

What is the difference between diffuse and defuse?

Many people find it difficult to remember the difference between defuse and diffuse, and when faced with the need for one of these words simply grab whichever one first comes to mind. Although these words sound quite similar, their meanings are rather distinct. Defuse means "to make less harmful, potent, or tense"; the word has another, helpfully literal, meaning, which is "to remove the fuse from." Diffuse means "not concentrated or localized"; it comes from the Latin word diffūsus ("spread over a wide area").

What is the difference between diffuse and infuse?

Diffuse is commonly found used as both adjective ("not concentrated or localized") and verb ("to pour out and permit or cause to spread freely," "to scatter"), while infuse is almost entirely restricted to use as a verb. While the meannings of diffuse are mainly concerned with outward movement, those of infuse are inward; the word has such meanings as "to steep in liquid (such as water) without boiling so as to extract the soluble constituents or principles," "to administer or inject by infusion," and "to cause to be permeated with something (such as a principle or quality) that alters usually for the better."

What does diffuse pain mean?

Diffuse pain is pain that is not concentrated or localized, being instead spread throughout a wider area of the body.

Synonyms

Adjective

See All Synonyms & Antonyms in Thesaurus
Choose the Right Synonym for diffuse

wordy, verbose, prolix, diffuse mean using more words than necessary to express thought.

wordy may also imply loquaciousness or garrulity.

a wordy speech

verbose suggests a resulting dullness, obscurity, or lack of incisiveness or precision.

the verbose position papers

prolix suggests unreasonable and tedious dwelling on details.

habitually transformed brief anecdotes into prolix sagas

diffuse stresses lack of compactness and pointedness of style.

diffuse memoirs that are so many shaggy-dog stories

Examples of diffuse in a Sentence

Adjective The forest was filled with a soft, diffuse light. a diffuse speech that took a great deal of time to make a very small point Verb The heat from the radiator diffuses throughout the room. The heat was diffused throughout the room. The photographer uses a screen to diffuse the light. an area of diffused light
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Adjective
The transients do not seem to be particles of nuclear fallout that have drifted down onto the photographic plate either, since such particles would produce foggy, diffuse spots, not pinpoint, star-like objects. —Keith Cooper, Space.com, 29 Oct. 2025 In this way, the technological sublime can be a diffuse feeling, encountered in fragments. —Joshua Rothman, New Yorker, 21 Oct. 2025
Verb
Stress thrives in silence; dialogue diffuses it. —Bruce Helmer, Twin Cities, 25 Oct. 2025 On April 25, 2023, police showed up to the Ocala neighborhood to diffuse the situation, according to body camera footage obtained by ABC News. —Caroline Blair, PEOPLE, 23 Oct. 2025 See All Example Sentences for diffuse

Word History

Etymology

Adjective

Middle English, "dispersed, verbose (of speech or writing)," borrowed from Middle French & Latin; Middle French diffus, borrowed from Latin diffūsus "spread over a wide area, (of writing) extensive, verbose," from past participle of diffundere "to pour out over a wide surface, spread, extend, squander" — more at diffuse entry 2

Verb

Middle English, in past participle diffusid, borrowed from Latin diffūsus, past participle of diffundere "to pour out over a wide surface, spread out, extend, squander," from dif-, assimilated form of dis- dis- + fundere "to pour, shed" — more at found entry 5

First Known Use

Adjective

1612, in the meaning defined at sense 1

Verb

15th century, in the meaning defined at transitive sense 1a

Time Traveler
The first known use of diffuse was in the 15th century

Phrases Containing diffuse

Rhymes for diffuse

See All Rhymes for diffuse

Browse Nearby Words

diffractometer
diffuse
diffuse nebula
See all Nearby Words

Cite this Entry

“Diffuse.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/diffuse. Accessed 4 Nov. 2025.

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Kids Definition

diffuse

1 of 2 adjective
dif·​fuse dif-ˈyüs How to pronounce diffuse (audio)
1
: using too many words : verbose
a diffuse writer
2
: poured or spread out : not concentrated
diffuse daylight
diffusely adverb
diffuseness noun

diffuse

2 of 2 verb
dif·​fuse dif-ˈyüz How to pronounce diffuse (audio)
diffused; diffusing
1
: to pour out and permit or cause to spread freely
2
: to go through or cause to go through diffusion

Medical Definition

diffuse

1 of 2 adjective
dif·​fuse dif-ˈyüs How to pronounce diffuse (audio)
: not concentrated or localized
diffuse sclerosis

diffuse

2 of 2 verb
dif·​fuse dif-ˈyüz How to pronounce diffuse (audio)
diffused; diffusing

transitive verb

1
: to subject (as a light beam) to diffusion
2
: to break up and distribute (incident light) by reflection (as from a rough surface)

intransitive verb

: to undergo diffusion

More from Merriam-Webster on diffuse

Nglish: Translation of diffuse for Spanish Speakers

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