Definition of "gerbil"

A member of one of several species of small, jumping, murine rodents, of the genus Gerbillus and certain other genera in subfamily Gerbillinae, with leaping powers resembling those of the jerboa, native to Africa, India, and Southern Europe.  examples

(intransitive) To rotate inside a monowheel or similar apparatus due to sudden acceleration or braking.  examples

(intransitive, slang) To insert a small animal (typically a gerbil, supposedly) into one's rectum (a sexual practice in urban myth).