diffuse

adjective
dif·​fuse | \di-ˈfyüs \

Definition of diffuse 

(Entry 1 of 2)

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

diffuse

verb
dif·​fuse | \di-ˈfyüz \
diffused; diffusing

Definition of diffuse (Entry 2 of 2)

transitive verb

1a : 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

Keep scrolling for more

Other Words from diffuse

Adjective

diffusely adverb
diffuseness noun

Verb

diffusible \di-​ˈfyü-​zə-​bəl \ adjective

Choose the Right Synonym for diffuse

Adjective

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

defuse or diffuse?

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. But it needn’t be this way: the meanings of these two are quite a bit different, and there is a simple way to differentiate between them. Defuse is formed by adding the prefix de- to the word fuse; you are removing the fuse (either literally or figuratively) when you defuse a situation, much as defanging something entails removing the fangs. Diffuse, when used as a verb, tends to carry meanings such as “spread” or “scatter.” Additionally, diffuse is the only one which may be found used as an adjective.

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
See More

Recent Examples on the Web: Adjective

Runner’s knee can feel like a dull, diffuse ache in and around the kneecap. SELF, "How to Know When It’s Safe to Run Through Knee Pain and When You Need to Stop," 7 Dec. 2018 Clint Watts, a senior fellow with the Foreign Policy Research Institute, said the diffuse nature of congressional and state races makes them a harder target than a single presidential election. Robert Mcmillan, WSJ, "Russian Hackers Largely Skipped the Midterms, and No One Really Knows Why," 12 Nov. 2018 The earlier data, from day 75, showed radio emissions that were relatively diffuse. John Timmer, Ars Technica, "Neutron-star merger blasted a jet of material through the debris," 5 Sep. 2018 The front is somewhat diffuse, shallow and does not have great impetus to move. Jeff Halverson, Washington Post, "Heavy showers and storms may target Washington region around sunset," 20 June 2018 But as the war has dragged on, growing more diffuse and complex, many international monitoring groups have essentially stopped counting. Megan Specia, New York Times, "How Syria’s Death Toll Is Lost in the Fog of War," 13 Apr. 2018 The galaxy’s spiral disk of stars is actually made of two parts: a thinner, denser region encompassed by a thicker, more diffuse region. Ramin Skibba, WIRED, "This Galactic Collision Shaped the History of the Milky Way," 8 July 2018 Researchers have slowly chipped away at that gap by adding to the census all the hot, diffuse gas in the enormous halos of galaxies and even larger galaxy clusters. Amina Khan, latimes.com, "After years of searching, scientists can finally account for all the normal matter in the universe," 20 June 2018 But her script is too diffuse—and too in love with the poetry of the Ukrainian women's black humor—to develop that theme with any force or clarity. Tony Adler, Chicago Reader, "The new Holodomor drama Sickle isn't sharp enough to draw much blood," 12 July 2018

Recent Examples on the Web: Verb

While bees that make large nests have no problems finding mates, there are many solitary species that rely on pheromones—small molecules that diffuse through the air and convey a specific message to their recipients. John Timmer, Ars Technica, "Gangs of beetle larvae lure fathers of their next meal into sex trap," 12 Sep. 2018 Once the cells are injected back into patients’ bodies, the antibodies latch onto the malignant proteins and help diffuse them. Preetika Rana, WSJ, "How China Is Evolving From a Maker of Copycat Medicines Into a Producer of Complex Drugs," 5 Aug. 2018 The efforts by the Justice Department over the last week to deliver documents to the House Republicans appear to have at least temporarily diffused a monthslong standoff with Congress. Mary Clare Jalonick, Anchorage Daily News, "DOJ gives Congress new classified documents on Russia probe," 24 June 2018 Robinson Cano and other could be seen coming over to help diffuse the situation. Ryan Divish, The Seattle Times, "Mariners show some pregame fight with an altercation in the clubhouse," 4 Sep. 2018 And as a finishing touch, new dimmers diffuse the lights in the modern torch-like sconces, which sit between two large mirrors that bounce around even more natural light. Taylor Murphy, House Beautiful, "An All-White Bathroom Starts Singing the Blues," 11 Sep. 2015 Having a third party as a mediator, such as a geriatric-care manager, is helpful in diffusing tense situations. Kelsey Mo, azcentral, "When and how to discuss senior-housing options with aging parents," 13 July 2018 Rod Rosenstein is trying to strike a balance here between diffusing the situation, but also protecting the rule of law and the institutional integrity of the department. Fox News, "Did an administration infiltrate the opposition's campaign?," 26 May 2018 American Airlines attempted to diffuse the situation. Justin Sayers, The Courier-Journal, "Louisville coach Chris Mack's flights get delayed like the rest of us," 17 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'diffuse.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of diffuse

Adjective

1612, in the meaning defined at sense 1

Verb

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

History and Etymology for diffuse

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

Keep scrolling for more

Learn More about diffuse

Statistics for diffuse

Last Updated

17 Dec 2018

Look-up Popularity

Time Traveler for diffuse

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

See more words from the same century

Keep scrolling for more

More Definitions for diffuse

diffuse

adjective

English Language Learners Definition of diffuse

 (Entry 1 of 2)

: spread out over a large space : not concentrated in one area

diffuse

verb

English Language Learners Definition of diffuse (Entry 2 of 2)

: to spread out : to move freely throughout a large area

: to exist or be known throughout an area

: to cause (light) to be soft and spread out

diffuse

verb
dif·​fuse | \di-ˈfyüz \
diffused; diffusing

Kids Definition of diffuse

: to spread or allow to spread freely The frosted window diffused the sunlight.

diffuse

adjective
dif·​fuse | \dif-ˈyüs \

Medical Definition of diffuse 

(Entry 1 of 2)

: not concentrated or localized diffuse sclerosis

diffuse

verb
dif·​fuse | \dif-ˈyüz \
diffused; diffusing

Medical Definition of diffuse (Entry 2 of 2)

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

Keep scrolling for more

More from Merriam-Webster on diffuse

Rhyming Dictionary: Words that rhyme with diffuse

Thesaurus: All synonyms and antonyms for diffuse

Spanish Central: Translation of diffuse

Nglish: Translation of diffuse for Spanish Speakers

Britannica English: Translation of diffuse for Arabic Speakers

Comments on diffuse

What made you want to look up diffuse? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

a typical or ideal example

Get Word of the Day daily email!

Test Your Vocabulary

Find the Cousins

  • a-large-tree-with-many-branches
  • Which pair shares a common word ancestor?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!