720 ILCS 5/2-5: "Conviction".

"Conviction" means a judgment of conviction or sentence entered upon a plea of guilty or upon a verdict or finding of guilty of an offense, rendered by a legally constituted jury or by a court of competent jurisdiction authorized to try the case without a jury. If judgment is withheld, the plea, verdict, or finding of guilty is not a conviction under Illinois law unless and until judgment is entered.