1.nounA system of recording or reproducing sound that uses two channels, each playing a portion of the original sound in such a way as to create the illusion of locating the sound at a particular position, each offset from the other, thereby more accurately imitating the location of the original sound when the recorded or reproduced sound is heard.
2.noun(by extension) Any object or device equipped with audio components that reproduces sound in stereo, such as a stereo console in the home.
"He liked to listen to classical music on his stereo."