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

Moby Thesaurus II by Grady Ward, 1.0:

57 Moby Thesaurus words for "granule":
   ace, atom, bit, breccia, dab, debris, detritus, dole, dot, dram,
   dribble, driblet, dwarf, farthing, fleck, flyspeck, fragment,
   gobbet, grain, granulet, gravel, grit, groat, hair, handful, iota,
   jot, little, little bit, minim, minimum, minutiae, mite, modicum,
   molecule, mote, nutshell, ounce, particle, pebble, pinch, pittance,
   point, sand, scruple, shingle, smidgen, smitch, speck, spoonful,
   spot, thimbleful, tiny bit, tittle, trifling amount, trivia,
   whit