1823 as a shortening of stereotype; 1876 as a shortening of stereoscope; 1954 (adj.) as a shortening of stereophonic; the noun meaning "stereophonic record or tape player" is recorded from 1964.
word-forming element, before vowels stere-, from comb. form of Greek stereos "solid" (see stereotype).
stereo- pref.
Solid; solid body: stereotropism.
Three-dimensional: stereochemistry.
equipment for sound recording and reproduction that utilizes two or more independent channels of information. Separate microphones are used in recording and separate speakers in reproduction; they are arranged to produce a sense of recording-hall acoustics and of the location of instruments within an orchestra. The effectiveness of stereophonic reproduction was demonstrated as early as 1933. Two-track stereophonic tape for the home became common in the 1950s and the stereophonic phonograph record, with two separate channels of information recorded in a single groove, in 1958. In the early 1970s, quadraphonic sound systems, employing four independent channels of information for even greater realism, became commercially available and later led to "surround-sound" systems