主しゅ調ちょう音おんしゅちょうおんMeanings1nounkeynote; tonicmusicIn music theory, the first note of a scale; the tonal center. Compare 主調 (しゅちょう), which refers to the main key of a piece.See also: 主調ハ長ちょう調ちょうの主しゅ調ちょう音おんはドです。The keynote of C major is C.曲きょくの最さい後ごは主しゅ