interval
C minor second
ClowerD♭upperm21 half steps
One half step, written as a second: the smallest distance between two notes with different letters.
On the keyboard
What is true of it
C up a minor second is D♭: 1 half step, and 2 letters counting both ends.
Turn it upside down — put the C on top — and it becomes a major seventh. The two numbers always add to nine, and the two sizes to twelve.
It is a dissonance.
Every interval on C
C → 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 · dissonanceC → Bmajor seventh · dissonance