An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) Any of numerous small Old World rodents of the family Muridae, especially of the genus Mus, introduced widely in other parts of the world.
2) Computers: A palm-sized, button-operated pointing device that can be used to move, select, activate, and change items on a computer screen (Dictionary.com).

M.E. mous (plural mis), from O.E. mus "small rodent;" cf. O.N., O.Fr., M.Du., Dan., Sw. mus, Du. muis, Ger. Maus, Pers. muš, as below.

Muš "mouse," dialectal Lori, Laki miš; Mid.Pers. mušk; cf. Skt. muš-, muš-; Gk. mys; L. mus; O.E. mys; Ger. Maus.