The Collaborative International Dictionary of English v.0.48:

Prunella \Pru*nel"la\, n. [NL., perhaps from G. br[ae]une
   quinsy, croup.] (Med.)
   (a) Angina, or angina pectoris.
   (b) Thrush.
       [1913 Webster]

   Prunella salt (Old Chem.), niter fused and cast into little
      balls.
      [1913 Webster] Prunella

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]

WordNet (r) 3.0 (2006):

Prunella
    n 1: small genus of perennial mostly Eurasian having terminal
         spikes of small purplish or white flowers [syn: Prunella,
         genus Prunella]
    2: type genus of the Prunellidae [syn: Prunella, genus
       Prunella]