The Collaborative International Dictionary of English v.0.48:

Tyro \Ty"ro\, n.; pl. Tyros. [L. tiro a newlylevied soldier, a
   beginner.]
   A beginner in learning; one who is in the rudiments of any
   branch of study; a person imperfectly acquainted with a
   subject; a novice. [Written also tiro.]
   [1913 Webster]

         The management of tyros of eighteen
         Is difficult.                            --Cowper.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tyro
    n 1: someone new to a field or activity [syn: novice,
         beginner, tyro, tiro, initiate]