Definition from Wiktionary, the free dictionary
- (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).
- (physiology): eccentric
Related terms 
having a common center
in the direction of contraction of a muscle