ACHELO'IS. 1. A surname of the Sirens, the daughters of Achelous and a muse. (Ov. Met. V. 552, xiv. 87; Apollod. i. 7. § 10.)

2. A general name for water-nymphs, as in Columella (x. 263), where the companions of the Pegasids are called Acheloides.[L. S.]