The Collaborative International Dictionary of English v.0.48:

Tryout \Try"out\, n.
   1. a test of the performance capability of a person, to
      ascertain fitness for a particular task; in sports, a test
      by which the fitness of a player or contestant to remain
      in a certain class is determined.
      [Webster 1913 Suppl. +PJC]

   2. (Theater) one or more performances of a play prior to the
      official opening, held at a location outside of the city
      where it is to be formally presented, conducted for the
      purpose of determining audience response or ascertaining
      weaknesses needing correction.
      [PJC]

WordNet (r) 3.0 (2006):

tryout
    n 1: trying something to find out about it; "a sample for ten
         days free trial"; "a trial of progesterone failed to
         relieve the pain" [syn: trial, trial run, test,
         tryout]
    2: a test of the suitability of a performer [syn: audition,
       tryout]