Green’s Dictionary of Slang

bull’s eye n.

[? the size and shape]

1. [late 17C] the vagina; joc. euph. coined by John Wilmot, Earl of Rochester (1647–80).

2. [late 17C–late 19C] a crown or five-shilling (25p) piece [later use is SE].

3. [early 19C–1950s] a large, round sweet.

4. [mid-19C] a bull’s-eye lantern.

5. [mid–late 19C] a thick, old-fashioned watch.