The term "d (Note)" refers to a specific musical note in the Western music scale. It is the second note in the D major scale and the tenth note in the C major scale. In terms of pitch, it is one whole step above C and one whole step below E. In the context of music notation, "d" can represent both the note itself and its position on a staff. It is commonly used in various musical compositions and can be played on different instruments, such as the piano or guitar, contributing to melodies and harmonies.