minnow

Short definition from Wiktionary

Noun

1. 1
   Any small fish.
2. 2
   Any small fish: The common minnow (Phoxinus phoxinus), a small freshwater fish of the carp family Cyprinidae which has a green back with black elongated blotches, commonly swimming in large shoals.
3. 3
   Any small fish: Chiefly with a qualifying word: any of a number of other (small) fish from the family Cyprinidae; also (chiefly US), other small (usually freshwater) fish from other families.
4. 4
   Any small fish: Synonym of galaxiid (“any member of the family Galaxiidae of mostly small freshwater fish of the Southern Hemisphere”); specifically, the common galaxias, inanga, or jollytail (Galaxias maculatus).
5. 5
   Any small fish: Synonym of stickleback (family Gasterosteidae).
6. 6
   A person or thing of relatively little consequence, importance, or value.
7. 7
   An artificial bait in the form of a small fish.

Adjective

1. 1
   Very small; tiny.

Verb

1. 1
   To fish for minnows (noun sense 1 and subsenses).
2. 2
   To fish, especially for trout, using minnows as bait.