paramere

Century Dictionary and Cyclopedia

1. n. In biology: A radiated part or organ; one of a set of radiating parts arranged like the spokes of a wheel about a common center; an actinomere: correlated with antimere, metamere, etc. The arms or rays of a starfish arc parameres in this sense.
2. n. Either half, right or left, of a bilaterally symmetrical animal: now oftener called antimere.
3. n. Either half, right or left, of one segment or somite of a bilaterally symmetrical animal.

Wiktionary

1. n. zoology One of the symmetrical halves of any one of the radii, or spheromeres, of a radiate animal, such as a starfish.

GNU Webster's 1913

1. n. (Zoöl.) One of the symmetrical halves of any one of the radii, or spheromeres, of a radiate animal, as a starfish.