any of numerous fishes of the class Chondrichthyes characterized by a cartilaginous skeleton and placoid scales: sharks; rays; skates
Any organism of the superorder Selachimorpha or subclass Elasmobranchii; an extant shark (or related species).
Pertaining to (what is now classified as) the superorder Selachimorpha or division Selachii, comprising the sharks; or, sometimes more broadly, to the subclass Elasmobranchii, including sharks, rays and related species.