In music theory, the first note of a scale, which serves as the tonal center.
ハ長調の主音はドです。
The tonic of C major is C.
曲の最後は主音で終わることが多い。
A piece often ends on the tonic.
syllabic
From 主 (main) + 音 (sound), a straightforward compound for the primary note of a scale.