Source : Webster's Revised Unabridged Dictionary (1913)

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

   {Prunella salt} (Old Chem.), niter fused and cast into little
      balls.