what is a shoul
shoal verb. The definition of a shoal is a large group, particularly of fish, or a sandy, shallow area of water. 1  An example of a shoal is a school of goldfish.2  An example of a shoal is a sandbar that makes a shallow place in the water.erb. The definition of a shoal is a large group, particularly of fish, or a sandy, shallow area of water. 1  An example of a shoal is a school of goldfish.