Shallow; of little depth.n. A place where the water of a stream, lake, or sea is of little depth; a sand-bank or bar; a shallow; more particularly, among seamen, a sand-bank which shows at low water: also used figuratively.To become shallow, or more shallow.Nautical, to cause to become shallow, or more shallow; proceed from a greater into a lesser depth of: as, a vessel in sailing shoals her water.n. A great multitude; a crowd; a throng; of fish, a school: as, a shoal of herring; shoals of people.To assemble in a multitude; crowd; throng; school, as fish.