The Collaborative International Dictionary of English v.0.48:

Retrial \Re*tri"al\, n.
   A secdond trial, experiment, or test; a second judicial
   trial, as of an accused person.
   [1913 Webster]

WordNet (r) 3.0 (2006):

retrial
    n 1: a new trial in which issues already litigated and to which
         the court has already rendered a verdict or decision are
         reexamined by the same court; occurs when the initial trial
         is found to have been improper or unfair due to procedural
         errors