What does "pointer" mean?

Pointer: One who, or that which, points. Specifically: (a) The hand of a timepiece. (b) (Zoöl.) One of a breed of dogs trained to stop at scent of game, and with the nose point it out to sportsmen. (c) pl. (Astron.) The two stars (Merak and Dubhe) in the Great Bear, the line between which points nearly in the direction of the north star. See Illust. of Ursa Major. (b) pl. (Naut.) Diagonal braces sometimes fixed across the hold.