A conch (pronounced as "konk" or "konch", IPA: /ˈkɒŋk/ or /ˈkɒntʃ/)^[1] is one of a number of different species of medium-sized to large saltwater snails or their shells. True conchs are marine gastropod molluscs in the family Strombidae, and the genus Strombus.

The name "conch" however, is often quite loosely applied in English-speaking countries to several kinds of very large snail-like shells of salt-water molluscs that are pointed at both ends. That is, a conch's shell has a high spire and a noticeable siphonal canal. Other species often called a "conch" include the crown conch Melongena species; the horse conch Pleuroploca gigantea; and the sacred chank or more correctly Shankha shell, Turbinella pyrum. None of these are in the family Strombidae, but instead in other families of the molluscs.^{[citation needed]}

The true conch species within the genus Strombus vary in size from fairly small to very large. Several of the larger species are economically important as food sources; these include the endangered queen conch or pink conch Strombus gigas, which very rarely may produce a pink, gem quality pearl.

About 74 species of the Strombidae family are living, and a much larger number of species exist only in the fossil record. ^[2] Of the living species, most are in the Indian and Pacific Oceans. Six species live in the greater Caribbean region, including the Queen Conch, and the West Indian Fighting Conch, Strombus pugilis