Definition of: antimere

(an′tə·mir) noun Biol.
A part symmetrical with, or corresponding to, a part on the opposite side of the main axis; an opposite, symmetrical, or homotypic part, as an arm of a starfish, or the right or left half of a bilaterally symmetrical animal: also called actinomere. [< ANTI- + Gk. meros part]
—an·ti·mer·ic (an′· tə·mer′ik) adjective
—an·tim·er·ism (an·tim′ə·riz′·əm) noun