Middle

Equally distant from the extreme either of a number of things or of one thing; mean; medial; as, the middle house in a row; a middle rank or station in life; flowers of middle summer; men of middle age.

Intermediate; intervening.

The point or part equally distant from the extremities or exterior limits, as of a line, a surface, or a solid; an intervening point or part in space, time, or order of series; the midst; central portion

the waist.

an intermediate part or section; "A whole is that which has beginning, middle, and end" - Aristotle