Source : Webster's Revised Unabridged Dictionary (1913)

Diffuser \Dif*fus"er\, n.
   One who, or that which, diffuses.

Source : WordNet®

diffuser
     n 1: baffle that distributes sound waves evenly [syn: {diffusor}]
     2: optical device that distributes the light of a lamp evenly
        [syn: {diffusor}]