Ratfishes

Part of speech: noun

Definitions

1. Cartilaginous deep-sea fishes related to sharks, having a long tapering tail and large eyes, known in the plural as a group of such species
2. Chimaera-like marine creatures with smooth skin, large eyes and a whiplike tail, the plural form naming several of these deep-water species
3. Deep-water cartilaginous fish closely related to sharks and rays, with a slender rat-like tail, referring to more than one of these species

Etymology: Ratfishes are the plural of "ratfish", a name for deep-sea chimaeras, the cartilaginous relatives of sharks and rays. The word is a plain compound of "rat" and "fish", and the "rat" element points to the creature's long, tapering tail, which narrows to a whip-like point behind a large body and head. Early naturalists and fishermen saw in these animals a rodent-like shape, and the name followed that resemblance. Because the word is a transparent compound, its history is mostly the history of its two parts. "Rat" has been in English since Old English, and "fish" is older still, so the combination needed no special coinage to be understood. The animals themselves are often called chimaeras, a name borrowed from Greek mythology, which is a separate term with its own story.