"Stereo” refers properly to a means of reproducing sound in two or more discrete channels to create a solid, apparently three-dimensional sound. Because in the early days only fanciers of high fidelity (or hi-fi) equipment could afford stereophonic sound, “stereo” came to be used as a substitute for “high fidelity,” and even “record player.” Stereo equipment (for instance a cheap portable cassette player) is not necessarily high fidelity equipment. Visual technology creating a sense of depth by using two different lenses can also use the root “stereo” as in “stereoscope."

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