bull's-eye

n. 1. (Naut.) A small circular or oval wooden block without sheaves, having a groove around it and a hole through it, used for connecting rigging. [ 1913 Webster ]

2. A small round cloud, with a ruddy center, supposed by sailors to portend a storm. [ 1913 Webster ]

3. A small thick disk of glass inserted in a deck, roof, floor, ship's side, etc., to let in light. [ 1913 Webster ]

4. A circular or oval opening for air or light. [ 1913 Webster ]

5. A lantern, with a thick glass lens on one side for concentrating the light on any object; also, the lens itself. Dickens. [ 1913 Webster ]

6. (Astron.) Aldebaran, a bright star in the eye of Taurus or the Bull. [ 1913 Webster ]

7. (Archery & Gun.) The center of a target. [ 1913 Webster ]

8. A thick knob or protuberance left on glass by the end of the pipe through which it was blown. [ 1913 Webster ]

9. A small and thick old-fashioned watch. [ Colloq. ] [ 1913 Webster ]

10. something that exactly succeeds in achieving its goal; as, to score a bull's eye.
Syn. -- bell ringer, mark. [ WordNet 1.5 ]