The Collaborative International Dictionary of English v.0.48:

Plebe \Plebe\ (pl[=e]b), n. [F. pl[`e]be, fr. L. plebs.]
   1. The common people; the mob. [Obs.]
      [1913 Webster]

            The plebe with thirst and fury prest. --Sylvester.
      [1913 Webster]

   2. [Cf. Plebeian.] A member of the lowest class in the
      military academy at West Point; also, a freshman at any
      military or naval academy. [Cant, U.S.]
      [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

plebe
    n 1: a military trainee (as at a military academy) [syn:
         cadet, plebe]