下属音是音阶的第四个音级，它之所以被称为下属音是因为它比属音低一个音级。例如在C大调中，G是属音，F就是下属音。

下属和弦是指任何基于下属音，而且使用同一音阶的音的和弦。例如在C大调中，下属音是F音，下属三和弦由F、A、C组成。

大调中的下属音三和弦是一个大三和弦，以IV表示(在C大调中的下属音三和弦为F-A-C);而在小调中的下属音三和弦则是一个小三和弦，以罗马数字iv表示(在C小调中的下属音三和弦为F-A♭-C)。

大调中的下属音七和弦是一个大七和弦，例如在C大调中的下属音三和弦为F-A-C-E，另一方面，在小调中的下属音七和弦则为一个小七和弦，在C小调中的下属音三和弦为F-A♭-C-E♭。

In music, the subdominant is the technical name for the fourth tonal degree of the diatonic scale. It is so called because it is the same distance "below" the tonic as the dominant is above the tonic - in other words, the tonic is the dominant of the subdominant. It also happens to be the note immediately "below" the dominant. It is sung as fa in solfege. In the C major scale (white keys on a piano, starting on C), the subdominant is the note F; and the subdominant chord uses the notes F, A, and C. In music theory, Roman numerals are used to symbolize the subdominant chord as 'IV' if it is within the major mode (because it is a major triad, for example F-A-C in C major) or 'iv' if it is within the minor mode (because it is a minor triad, for example F-A♭-C in C minor).