The American shad (Alosa sapidissima) is a species of anadromous clupeid fish naturally distributed on the North American coast of the North Atlantic, from Newfoundland to Florida, and as an introduced species on the North Pacific coast. The American shad is not closely related to the other North American shads. Rather, it seems to form a lineage that diverged from a common ancestor of the European taxa before these diversified. The name "shad" derives from the Old English sceadd, meaning "herring"; it is a cognate to Irish, Welsh, and Scottish Gaelic words for herring.