An overtone is any frequency higher than the fundamental frequency of a sound. The fundamental and the overtones together are called partials. Harmonics are partials whose frequencies are whole number multiples of the fundamental (including the fundamental which is 1 times itself). These overlapping terms are variously used when discussing the acoustic behavior of musical instruments. Due to a translation error in its coining, Alexander J. Ellis strongly suggested avoiding the term overtone in deference to upper partial (simple) tones.