diffuser

noun

dif·​fus·​er di-ˈfyü-zər 

plural diffusers

1

: one that diffuses: such as

a

: a device (such as a reflector) for distributing the light of a lamp evenly

b

: a screen (as of cloth or frosted glass) for softening lighting (as in photography)

c

: a device (such as slats at different angles) for deflecting air from an outlet in various directions

d

: a device that produces a fine mist of water and often essential oils

2

: a device for reducing the velocity and increasing the static pressure of a fluid passing through a system

Examples of diffuser in a Sentence

Recent Examples on the Web

For best results, use a hair dryer that has a diffuser for curls that are defined, but not frizzy. —Audrey Noble, InStyle, 10 Mar. 2026

The ground-effect tunnels that defined the 2022 through 2025 era (that Red Bull’s Verstappen dominated, while Mercedes mostly struggled) have disappeared, replaced by flatter floors and larger diffusers. —Brad Spurgeon, Robb Report, 9 Mar. 2026

To scale up on the theme, add curtains or drapery for a peekaboo moment, and pique curiosity by scentscaping with candles or glass diffusers that exude notes of cedarwood and dark florals such as jasmine. —Yelena Moroz Alpert, Architectural Digest, 9 Mar. 2026

After applying this product to wet hair with a squirt of styling gel, a quick shake of her curls, and a hit of the diffuser, my curls were noticeably more defined and less frizzy, especially at the roots—even on a gross, 70% humidity day at that. —Eden Stuart, Glamour, 5 Mar. 2026

Word History

Etymology

diffuse entry 2 + -er entry 2

First Known Use

1645, in the meaning defined at sense 1

Rhymes for diffuser

• abuser
• accuser
• boozer
• bruiser
• chooser
• cruiser
• loser
• user
• multiuser