Emily Dickinson Lexicon

SHOAL, n. [Sax. sceol, a crowd. It should rather be written Shole.]

1. A great multitude assembled; a crowd; a throng; as, shoals of people. Immense shoals of herring appear on the coast in the spring. The vices of a prince draw shoals of followers. – Decay of Piety.
2. A place where the water of a river, lake or sea is shallow or of little depth; a sand-bank or bar; a shallow. The entrance of rivers is often rendered difficult or dangerous by shoals.