The Collaborative International Dictionary of English v.0.48:

Opuscle \O*pus"cle\ ([-o]*p[u^]s"'l), Opuscule \O*pus"cule\
   ([-o]*p[u^]s"k[-u]l), n. [L. opusculum, dim. of opus work:
   cf. F. opuscule.]
   A small or petty work.
   [1913 Webster]