A jury is a group that decides a contest together. If you enter the County Fair's competition for best homemade pie, you'd better hope that the jury likes peanut-butter-coconut-pecan pie. It was a bold choice.
A jury is any group that makes a group decision. In the County Fair, the stakes aren't so high — just respect for your baking skills or pig-raising talents. But many juries are convened by courts to decide whether someone is innocent or guilty. In this case, the jury is sworn to act according to the law. Jury comes from the Old French word for "oath," pointing to the promise to deliver the truth that a jury swears to.
