"place of shallow water in a stream, lake, or sea," Middle English sholde, from Old English scealde (adj.) "shallow, of little depth," an oblique case of sceald "shallow," from Proto-Germanic *skala- (source also of Swedish skäll "thin;" Low German schol, Frisian skol "not deep"), a word of uncertain origin. The terminal -d in English was dropped 16c. Shoaler "sailor in the coastal trade" is by 1891.
"large number, great multitude" (especially of fish), 1570s, a word of uncertain origin. It is apparently identical with Middle English scole "a troop, throng, crowd," from Old English scolu "band, troop, crowd of fish" (see school (n.2)), but it also might be a 16c. adoption of the cognate Middle Dutch schole.
updated on August 25, 2022