shoal

adj

1. (archaic)Shallow.

   “shoal water”

   “But that part of the coast being shoal and bare, / And rough with reefs which ran out many a mile, / His port lay on the other side o' the isle.”

   “All told, we had scarce two miles to run; but the navigation was delicate, the entrance to this northern anchorage was not only narrow and shoal, but lay east and west, so that the schooner must be nicely handled to be got in.”

noun

1. A sandbank or sandbar creating a shallow.

   “'Twas early June, the new grass was flourishing everywheres, the posies in the yard—peonies and such—in full bloom, the sun was shining, and the water of the bay was blue, with light green streaks where the shoal showed.”

   “The god himself with ready trident stands, / And opes the deep, and spreads the moving sands, / Then heaves them off the shoals.”

2. A shallow in a body of water.

   “The depth of your pond should be six feet; and on the sides some shoals for the fish to sun themselves in and to lay their spawn.”

   “Wolsey, that once trod the ways of glory, / And sounded all the depths and shoals of honour.”

3. Any large number of persons or things.

   “Shoals of tourists”

   “great shoals of people”

4. (collective)A large number of fish (or other sea creatures) of the same species swimming together.

   “c. 1661, Edmund Waller, On St. James's Park Beneath, a shoal of silver fishes glides.”

   “He came directly from the shoal which we had just before entered, and in which we had struck three of his companions, as if fired with revenge for their sufferings.”

verb

1. To arrive at a shallow (or less deep) area.
2. (transitive)To cause a shallowing; to come to a more shallow part of.

   “Noting the rate at which she shoals her water -[…]”

3. To become shallow.

   “The colour of the water shows where it shoals.”

4. To collect in a shoal; to throng.

   “The fish shoaled about the place.”