\Pin"nule\, n. [L. pinnula, dim. of pinna feather: cf.
F. pinnule.]
1. (Bot.) One of the small divisions of a decompound frond or
   leaf. See Illust. of {Bipinnate leaf}, under {Bipinnate}.
2. (Zo["o]l.) Any one of a series of small, slender organs,
   or parts, when arranged in rows so as to have a plumelike
   appearance; as, a pinnule of a gorgonia; the pinnules of a
   crinoid.