Major second interval

Major second in musical notationThe major second interval consists of two notes with one whole step distance. For example, C to D note will result in this musical interval.

The major second interval is abbreviated M2 whereas the minor second is abbreviated m2. An alternate spelling of major second is diminished third.
Keyboard major second interval 
A major second with C to D on the keyboard.

Listen to major second interval (C-D):

In scales, this interval is the most frequent. In the major scale, the major second interval is represented five times. For example, in C major C, D, E, F, G, A, B, C the major seconds are C-D, D-E, F-G, G-A and A-B.

The major second is also present in some chords, such as, sus2 and add2. The number two are pointing out that a second interval is included in the chord. For example, Csus2 consisting of the notes C, D, G.

Ascending major second intervals

A list with ascending major second intervals:

Descending major second intervals

A list with descending major second intervals:

Enharmonic notes such as Cb and Fb are leaved out.