sound [OE] There are four different ‘sounds’ in English. The one relating to noise is Middle English from Latin sonus. Related words are dissonance [LME] ‘inharmonious’; resonance [LME] ‘echo, resound’; resonant [L16th]; resound [LME]; and sonorous [E17th].

Sound [ME], meaning ‘in good condition, not damaged or diseased’, is from Old English gesund. In Middle English the prominent sense was ‘uninjured, unwounded’, developing into ‘having well-grounded opinions’ The phrase as sound as a bell appeared in the late 16th century. This puns on the first meaning of sound, and also on the fact that a cracked bell will not ring true. The third sound [LME] ‘ascertain the depth of water’ is from Old French sonder, based on Latin sub- ‘below’ and unda ‘wave’. The final one for a narrow stretch of water is Middle English from Old Norse sund ‘swimming, strait’, related to *swim.