詞源不確定，可能來自 scad 的復數形式，引申詞義大量，許多。
In July, 1834, as Mr. Yarrell informs us, most extraordinary shoals passed up the channel along the coast of Glamorganshire; their passage occupied a week, and they were evidently in pursuit of the fry of the herring. The water appeared one dark mass of fish, and they were caught by cart-loads, and might even be baled out of the water by the hands alone. ["British Fish and Fisheries," 1849]
來自《權威詞典》
來自《簡明英漢詞典》