The Collaborative International Dictionary of English v.0.48:

Prunella \Pru*nel"la\, Prunello \Pru*nel"lo\, n. [F. prunelle,
   probably so called from its color resembling that of prunes.
   See Prune, n.]
   A smooth woolen stuff, generally black, used for making
   shoes; a kind of lasting; -- formerly used also for
   clergymen's gowns.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Prunello \Pru*nel"lo\, n. [F. prunelle, dim. of prune. See
   Prune a plum.]
   A species of dried plum; prunelle.
   [1913 Webster]