In baseball, the arm and body movements a pitcher makes just before throwing the ball are collectively called the windup. Sports announcers repeat this phrase throughout baseball games: "Here's the windup...and the pitch!"
You can also use windup to mean "conclusion." At the windup of a lengthy meeting, everyone will collect their papers and laptops, and several people will yawn and stretch. The windup of a political campaign might include one last speech and a full-page ad in a newspaper, just before the election. This is the oldest meaning of windup, dating from the 16th century. As an adjective, windup can mean "operated by a mechanism," like a windup toy.