Voir dire is the process by which attorneys and judges question prospective jurors before a trial to assess their suitability to serve. It is also used, less commonly, to describe a preliminary examination of a witness or expert to determine competency. The term is older than the American legal system and considerably more interesting than most jury selection coverage suggests. What It Is Before a jury trial begins, a pool of prospective jurors — the venire — is summoned to the courthouse.