—n. 1. any of numerous small Old World rodents of the family Muridae, esp. of the genus Mus, introduced widely in other parts of the world.
2. any similar small animal of various rodent and marsupial families.
3. a quiet, timid person.
4. Computers.a palm-sized, button-operated device that can be slid on wheels or ball bearings over a desktop to move the cursor on a CRT to any position, or slid over a drawing in order to recreate the drawing on a CRT. Cf. joystick (def. 2).
5. Informal.a swelling under the eye, caused by a blow or blows; black eye.
6. Slang.a girl or woman.
—v.t. 1. to hunt out, as a cat hunts out mice.
2. Naut.to secure with a mousing.
—v.i. 1. to hunt for or catch mice.
2. to prowl about, as if in search of something: The burglar moused about for valuables. 3. to seek or search stealthily or watchfully, as if for prey.