KEY Meaning of KEY in English n. 1.Lock opener.2.Clew, guide, explanation, solution, elucidation, clavis .3.Tonic, ~-note, fundamental note, first note of the scale.4.Wedge, clamp.5.( Mus. ) Lever ( in an instrument ). Soule. Dictionary of English synonyms. Словарь английских синонимов. 2012