: spread out over a large space : not concentrated in one area
The forest was filled with a soft, diffuse light.
diffuse pain
diffuses; diffused; diffusing
1
a
: to spread out : to move freely throughout a large area
The heat from the radiator diffuses throughout the room.
The heat was diffused throughout the room.
b
: to exist or be known throughout an area
Their culture gradually diffused [=spread] westward.
diffusing their ideas
2
: to cause (light) to be soft and spread out
The photographer uses a screen to diffuse the light.
an area of diffused light
Cite this Entry
“Diffuse.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/diffuse. Accessed 20 Jun. 2026.
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