Source : Webster's Revised Unabridged Dictionary (1913)

Spherule \Spher"ule\, n. [L. spherula: cf. F. sph['e]rule.]
   A little sphere or spherical body; as, quicksilver, when
   poured upon a plane, divides itself into a great number of
   minute spherules.

Source : WordNet®

spherule
     n : a small sphere