Audio and electronics
In audio, "fidelity" denotes how accurately a copy reproduces its source. For example, a worn gramophone record will have a lower fidelity than one in good condition, and a recording made by a low budget record company in the early 20th century is likely to have significantly less audio fidelity than a good modern recording. In the 1950s, the terms "high fidelity" or "hi-fi" were popularized for equipment and recordings which exhibited more accurate sound reproduction. Similarly in electronics, fidelity refers to the correspondence of the output signal to the input signal, rather than sound quality, as in the popular internet connection technology "Wi-Fi".