High fielity or hi-fi reproduction is a term used by home stereo listeners and home audio enthusiasts (audiophiles) to refer to high-quality reproduction of sound or images that is very faithful to the original master recording. High fidelity equipment has minimal or unnoticeable amounts of noise and distortion and an accurate frequency response as set out in 1973 by the German Deutsches Institut für Normung (DIN) standard DIN 45500. The term was most widely used in this strict sense in the 1950s and 1960s; in subsequent decades, the term was applied more loosely to any mid-level stereo system. In the 2000s, the term "hi-fi" for expensive high quality home audio electronics was largely replaced with the term "high-end audio".