Longjaw

Part of speech: noun, adjective

Definitions

1. A fish species named for its notably elongated lower jaw, such as the longjaw cisco of northern lakes
2. Any of several fish whose jaws extend far beyond the usual length, including certain freshwater whitefish and mudsuckers
3. A kind of fish distinguished by a markedly long jaw, found in cold lakes and coastal mudflats

Etymology: Longjaw is about as transparent as English compounds get: "long" joined to "jaw," describing a fish with an elongated lower or upper jaw. The compound has no story beyond its parts, so the useful detail lies in the second element. "Jaw" traces back to a Middle English word for the bony framework of the mouth, and the fish name simply adds the descriptive first element to it. The naming logic is what makes the word work. Fishermen and naturalists often named species by the most conspicuous physical trait, and a jaw that projects well beyond the rest of the head is hard to miss. In this way the word reads as a field description turned into a common name, a pattern shared by many English fish names built from a body part plus an adjective.