noun (n)

• the act of testing something(noun.act)

  Example:
  In the experimental trials the amount of carbon was measured separately.
  He called each flip of the coin a new trial.
  

  Synonym:
  run, test
  

  source: wordnet30
• trying something to find out about it(noun.cognition)

  Example:
  A sample for ten days free trial.
  A trial of progesterone failed to relieve the pain.
  

  Synonym:
  test, trial run, tryout
  

  source: wordnet30
• the act of undergoing testing(noun.act)

  Example:
  Candidates must compete in a trial of skill.
  

  Synonym:
  test
  

  source: wordnet30
• (law) the determination of a person's innocence or guilt by due process of law(noun.act)

  Example:
  He had a fair trial and the jury found him guilty.
  Most of these complaints are settled before they go to trial.
  

  source: wordnet30
• (sports) a preliminary competition to determine qualifications(noun.event)

  Example:
  The trials for the semifinals began yesterday.
  

  source: wordnet30
• an annoying or frustrating or catastrophic event(noun.event)

  Example:
  His mother-in-law's visits were a great trial for him.
  

  Synonym:
  tribulation, visitation
  

  source: wordnet30
• The act of trying or testing in any manner.(noun)

  source: webster1913