any one of numerous species of small rodents belonging to the genus mus and various related genera of the family muridae.  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.-a knob made on a rope with spun yarn or parceling to prevent a running eye from slipping.-same as 2d mousing, 2.-a familiar term of endearment.-a dark-colored swelling caused by a blow.-a match used in firing guns or blasting.-to watch for and catch mice.-to watch for or pursue anything in a sly manner; to pry about, on the lookout for something.-to tear, as a cat devours a mouse.-to furnish with a mouse; to secure by means of a mousing. see mouse, n., 2.