interval
C major seventh
ClowerBupperM711 half steps
Eleven half steps: a half step short of the octave, which is why it leans on it.
On the keyboard
What is true of it
C up a major seventh is B: 11 half steps, and 7 letters counting both ends.
Turn it upside down — put the C on top — and it becomes a minor second. The two numbers always add to nine, and the two sizes to twelve.
It is a dissonance.
Every interval on C
C → D♭minor second · dissonanceC → Dmajor second · dissonanceC → E♭minor third · imperfect consonanceC → Emajor third · imperfect consonanceC → Fperfect fourth · perfect consonanceC → F♯augmented fourth · dissonanceC → G♭diminished fifth · dissonanceC → Gperfect fifth · perfect consonanceC → A♭minor sixth · imperfect consonanceC → Amajor sixth · imperfect consonanceC → B♭minor seventh · dissonance