Stereophonic sound, or more commonly stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. Wikipedia

Method of sound reproduction using two audio channels Wikidata

A 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. Wiktionary

System. Wiktionary (translation)