Any one of many species of marine bivalve shells of the genus
Mytilus, and related genera, of the family
Mytidæ. The common mussel (
Mytilus edulis; see
Illust. under
Byssus), and the larger, or horse, mussel (
Modiola modiolus), inhabiting the shores both of Europe and America, are edible. The former is extensively used as food in Europe. [
1913 Webster]