The Collaborative International Dictionary of English v.0.48:

Granule \Gran"ule\ (gr[a^]n"[-u]l), n. [L. granulum, dim. of
   granum grain: cf. F. granule. See Grain a kernel.]
   A little grain; a small particle; a pellet.
   [1913 Webster]

WordNet (r) 3.0 (2006):

granule
    n 1: a tiny grain