noun
middle refers to the point or part equally distant from either or all sides or extremities and may apply to space, time, or a sequence the middle of the stage, the middle of the day; center more precisely stresses the point equidistant from the bounding lines or surfaces of a plane or solid figure the center of a circle, the center of the globe and is often used figuratively the center of town, a trade center; midst, used in prepositional phrases, denotes a middle part that is surrounded by persons or things or a middle point in some action in the midst of a crowd, in the midst of one's work
See middle in Webster's New World Roget's A-Z Thesaurus II
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