midpoint

noun

1. a point at or near the middle of, or equidistant from, both ends, as of a line: the midpoint of a boundary.
2. a point in time halfway between the beginning and the end, as of a process, event, or situation: the midpoint of the negotiations.
3. Geometry. the point on a line segment or an arc that is equidistant, when measured along the line or the arc, from both endpoints.
4. Statistics. median(def 3).
5. Astrology. the point on the arc that is equidistant from two planets: regarded as a sensitive point and used in horoscopic interpretations.

noun

1. the point on a line that is at an equal distance from either end
2. a point in time halfway between the beginning and end of an event

n.late 14c., from mid + point (n.).