mermaid

n. [ AS. mere lake, sea. See Mere lake, and maid. ] A fabled marine creature, typically represented as having the upper part like that of a woman, and the lower like a fish; a sea nymph, sea woman, or woman fish. [ 1913 Webster ]

☞ Chaucer uses this word as equivalent to the siren of the ancients. [ 1913 Webster ]

Mermaid fish (Zool.) the angel fish (Squatina). --
Mermaid's glove (Zool.), a British branched sponge somewhat resembling a glove. --
Mermaid's head (Zool.), a European spatangoid sea urchin (Echinocardium cordatum) having some resemblance to a skull. --
Mermaid weed (Bot.), an aquatic herb with dentate or pectinate leaves (Proserpinaca palustris and Proserpinaca pectinacea). [ 1913 Webster ]