bullseye

Etymology

From bull's + eye. May have come from the practice of English archers shooting an arrow through the eye socket of a bull's skull as a test of skill. The connection to philately comes from the shape of the key plate or vignette.

noun

1. (military, firearms) The centre of a target, inside the inner and magpie.
2. A shot which hits the centre of a target.
3. (darts) The two central rings on a dartboard.
4. A hard striped peppermint-flavoured boiled sweet.
5. (nautical, obsolete) Thick glass set into the side of a ship to let in light.
6. A hand-cancelled postmark issued by a counter clerk at a post office, typically done on a receipt for proof of mailing.
7. The central part of a crown glass disk, with concentric ripple effect.
8. A convex glass lens which is placed in front of a lamp to concentrate the light so as to make it more conspicuous as a signal; also the lantern itself.
   He put on his fur coat and hat and went out into the hall. There he paused, hearing the slow heavy tread of the policeman on the pavement outside and seeing the flash of the bull's-eye reflected in the window. 1890, Oscar Wilde, chapter XII, in The Picture of Dorian Gray
9. (military, by extension) A commonly-known reference point used when indicating the location or direction of something.
10. (architecture) An oculus.
11. (UK, slang) A £50 banknote.
12. (philately, informal) Any of the first postage stamps produced in Brazil from 1843.

intj

1. A cry when someone hits the bullseye of a target.
2. (by extension) A response to a totally accurate statement.
   —Did John steal the petty cash? —Bullseye.