Chipmunk \Chip"munk`\, n. [Indian name.]

(Zo["o]l.) A squirrel-like animal of the genus Tamias, sometimes called the striped squirrel, chipping squirrel, ground squirrel, hackee. The common species of the United States is the Tamias striatus. [Written also chipmonk, chipmuck, and chipmuk.]

Source: Webster's Revised Unabridged Dictionary (1913)