Any one of numerous species of small rodents belonging to the genus Mus and various related genera of the family Muridæ. The common house mouse (Mus musculus) is found in nearly all countries. The American white-footed, or deer, mouse (Hesperomys leucopus) sometimes lives in houses. See Dormouse, Meadow mouse, under Meadow, and Harvest mouse, under Harvest.
- Any of numerous small rodents of the families Muridae and Cricetidae, such as the common house mouse (Mus musculus), characteristically having a pointed snout, small rounded ears, and a long naked or almost hairless tail.
- Any of various similar or related animals, such as the jumping mouse, the vole, or the jerboa.
- A cowardly or timid person.
- Informal A discolored swelling under the eye caused by a blow; a black eye.
- Computer Science A hand-held, button-activated input device that when rolled along a flat surface directs an indicator to move correspondingly about a computer screen, allowing the operator to move the indicator freely, as to select operations or manipulate text or graphics.
- To hunt mice.
- To search furtively for something; prowl.