Noah Webster's New International Dictionary of the English Language

1. (n.) A great multitude assembled; a crowd; a throng; -- said especially of fish; as, a shoal of bass.

2. (v. i.) To assemble in a multitude; to throng; as, the fishes shoaled about the place.

3. (a.) Having little depth; shallow; as, shoal water.

4. (n.) A place where the water of a sea, lake, river, pond, etc., is shallow; a shallow.

5. (n.) A sandbank or bar which makes the water shoal.

6. (v. i.) To become shallow; as, the color of the water shows where it shoals.

7. (v. t.) To cause to become more shallow; to come to a more shallow part of; as, a ship shoals her water by advancing into that which is less deep.