[verb dih-fyooz; adjective dih-fyoos]

verb (used with object), dif·fused, dif·fusing.

verb (used without object), dif·fused, dif·fusing.

to spread.
Physics. to intermingle by diffusion.


Origin of diffuse

1350–1400; Middle English (< Anglo-French) < Latin diffūsus spread, poured forth. See dif-, fuse2
Related formsdif·fuse·ly [dih-fyoos-lee] /dɪˈfyus li/, adverbdif·fuse·ness, nounin·ter·dif·fuse, verb, in·ter·dif·fused, in·ter·dif·fus·ing.non·dif·fuse, adjectivenon·dif·fused, adjectivenon·dif·fus·ing, adjectiveo·ver·dif·fuse, verb, o·ver·dif·fused, o·ver·dif·fus·ing, adjectiveo·ver·dif·fuse·ly, adverbo·ver·dif·fuse·ness, nounre·dif·fuse, verb, re·dif·fused, re·dif·fus·ing.un·dif·fused, adjectivewell-dif·fused, adjective
Can be confuseddefuse diffuse
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for diffuse

Contemporary Examples of diffuse

Historical Examples of diffuse

  • Flora, who had seemed enchanting in all she said and thought, was diffuse and silly.

    Little Dorrit

    Charles Dickens

  • Knowledge is not necessarily light; and it is light, not knowledge, that we have to diffuse.

    A Dish Of Orts

    George MacDonald

  • They diffuse what is known and forget what remains to be known.

  • The message was explicit, and, in the point of affection, diffuse.

    The Prisoner

    Alice Brown

  • A soft glow seemed to diffuse from the man's clothing and body.

    The Whispering Spheres

    Russell Robert Winterbotham

British Dictionary definitions for diffuse


verb (dɪˈfjuːz)

to spread or cause to spread in all directions
to undergo or cause to undergo diffusion
to scatter or cause to scatter; disseminate; disperse

adjective (dɪˈfjuːs)

spread out over a wide area
lacking conciseness
(esp of some creeping stems) spreading loosely over a large area
characterized by or exhibiting diffusiondiffuse light; diffuse reflection
botany (of plant growth) occurring throughout a tissue
Derived Formsdiffusely (dɪˈfjuːslɪ), adverbdiffuseness, noundiffusible (dɪˈfjuːzəbəl), adjectivediffusibility or diffusibleness, noun

Word Origin for diffuse

C15: from Latin diffūsus spread abroad, from diffundere to pour forth, from dis- away + fundere to pour


Avoid confusion with defuse
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for diffuse

1520s (transitive), 1650s (intransitive), from Latin diffusus, past participle of diffundere "to pour out or away" (see diffusion). Related: Diffused; diffusing.


early 15c., from Latin diffusus (see diffuse (v.)).

Online Etymology Dictionary, © 2010 Douglas Harper

diffuse in Medicine




Not limited to one tissue or location; widespread.


To spread or to be spread widely, as through a tissue.
Related formsdif•fusi•ble (-fyōōzə-bəl) adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.