(zoology) 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.

(zoology) Any organism of the superorder Selachimorpha or subclass Elasmobranchii; an extant shark (or related species).

plural of selachian