bull's eye vs midpoint

bull's eye and midpoint both are nouns.

Word	Noun	Adjective	Verb	Adverb
bull's eye	Yes	No	No	No
midpoint	Yes	No	No	No

As nouns, midpoint is a hypernym of bull's eye; that is, midpoint is a word with a broader meaning than bull's eye:

bull's eye: the center of a target
midpoint: a point equidistant from the ends of a line or the extremities of a figure

Other hypernyms of bull's eye include center, centre.

bull's eye (noun)	midpoint (noun)
in target shooting: a score made by hitting the center of the target	a point equidistant from the ends of a line or the extremities of a figure
something that exactly succeeds in achieving its goal
the center of a target