noun
related key
Music theory term for a key closely related to another, typically sharing many common tones. Used in classical harmony and modulation contexts.
ハ長調の近親調にはト長調やヘ長調などがある。
Related keys to C major include G major and F major.
属調 is the dominant key (a fifth above), which is one type of 近親調.
下属調 is the subdominant key (a fifth below), another type of 近親調.
Compound of 近親 (kinshin, 'close relative') and 調 (chō, 'key' in music). The term is a direct calque from Western music theory 'related key'.