shad

Etymology

From Old English sceadd, possibly from Celtic (compare Scottish Gaelic sgadan (“herring”), Welsh ysgadan) or from Scandinavian/North Germanic (compare dialectal Norwegian skadd (“small whitefish”), Old Norse skata (“kind of fish”)), but the order of borrowing is unclear and the ultimate origin of these words is obscure.

noun

1. Any one of several species of food fishes that make up the genus Alosa in the family Clupeidae, to which the herrings also belong; river herring.
   Each river had its village and its iron bridge that the train crossed with a blast of its whistle, and the girls bathing in the icy water leaped like shad as it passed, unsettling travelers with their fleeting breasts. 2003, Gabriel García Márquez, chapter 1, in Edith Grossman, transl., Living to Tell the Tale
2. (South Africa) Any bluefish of species Pomatomus saltatrix.