1250-1300;Middle Englishturbut < Anglo-French;Old Frenchtourbot < Medieval Latinturb(ō) turbot (Latin: top; apparently applied to the fish because of its outline; see turbine, turbit) + Old French-ot noun suffix
"large flat fish," c.1300, from O.Fr. turbut (12c.), probably from a Scand. source (cf. O.Swed. törnbut, from törn "thorn" + but "flatfish;" see halibut). But OED says of uncertain origin and speculates on a connection to L. turbo "spinning top."