1 n : discreteparticle of dirt or other material. [ASTM F1241] Also see dirt. 2 n (dust) : discreteparticle of material that can usually be removed by (nonetching) cleaning. [SEMI M10-89] 3 adj : describes material in small, discrete pieces; anything that is not a fiber and has an aspect ratio of less than 3 to 1. Examples are dusts, fumes, smokes, mists, and fogs.
