Sternoptychid

Part of speech: noun

Definitions

1. A small deep-sea fish with a laterally compressed body and light-producing organs, belonging to the hatchetfish family
2. Any of the silvery, deep-water marine fishes in the family Sternoptychidae, often called hatchetfishes
3. A bioluminescent ocean-dwelling fish that lives at great depths and has a flattened, hatchet-like silhouette

Etymology: The name describes the fish's chest. It comes from Greek "sternon," meaning "breastbone" or "chest," and "ptyx," meaning "fold" or "pleat." Sternoptychids have a deep, compressed body with a sharp keel along the belly, which gives them a breastplate-like profile when seen from the side. The family name, Sternoptychidae, was coined in Latin-style zoological form from those Greek roots. The English word is simply that family name with the ordinary English suffix "-id," which marks a member of a biological family, so a sternoptychid is any fish in that group. Most species are small, often only a few centimetres long, and live in the dark open ocean, where their silvery sides reflect faint light and their rows of light-producing organs help them blend in from below.