Adjective

(en adjective)

(geometry) Having a common center.

(physiology) (of a motion) in the direction of contraction of a muscle. (E.g. extension of the lower arm via the elbow joint while contracting the triceps and other elbow extensor muscles; closing of the jaw while flexing the masseter).

Antonym: eccentric. Concentric and eccentric movements are collectively referred to as isotonic (with motion), the antonym of which is isometric (without motion).

Adjective

(-)

Having the same spatial limits or boundaries; sharing the same area.

The city and county of San Francisco are coextensive .

Occurring over the same period of time; contemporaneous.

* 1946 , (Bertrand Russell), History of Western Philosophy , I.30:

His life is almost co-extensive with one of the most disastrous periods in Roman history.

(logic) Having the same extension—the object or set of objects to which a term refers.

* {{quote-book, year=1995, title=A Companion to Metaphysics, author=Jaegwon Kim, Ernest Sosa

citation , passage=Coextensive expressions with different intensions cannot in general be substituted for one another within an expression e'' while preserving the extension of ''e (assuming that the extension of a declarative sentence is its truth value).}}