The Collaborative International Dictionary of English v.0.48:

Freshman \Fresh"man\, n.; pl. Freshmen.
   A novice; one in the rudiments of knowledge; especially, a
   student during his first year in a high school, college, or
   university.

   Syn: frosh.
        [1913 Webster]

              He drank his glass and cracked his joke,
              And freshmen wondered as he spoke.  --Goldsmith.
        [1913 Webster]

   Freshman class, the lowest of the four classes in an
      American college. [ U. S.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

freshman class
    n 1: the first class in college or high school