The Collaborative International Dictionary of English v.0.48:
Diffuser \Dif*fus"er\, n. One who, or that which, diffuses. [1913 Webster]WordNet (r) 3.0 (2006):
diffuser n 1: baffle that distributes sound waves evenly [syn: diffuser, diffusor] 2: optical device that distributes the light of a lamp evenly [syn: diffuser, diffusor]