- A percussion|percussive note in which the drumstick hits both the drum head|head and the rim of the drum.
- colloquial A percussive "sting" or flourish used to punctuate a joke in a cabaret or vaudeville act.
Technically, the sting used to punctuate a joke is not a rimshot. A rimshot is a particular note (as in sense 1 above); a sting is a percussive figure consisting of several notes, perhaps a roll followed by a crash cymbal.
Wikipedia article on w:Sting (percussion)|sting (percussion)