In classical music from Western culture, a seventh is a musical interval encompassing seven staff positions (see Interval number for more details), and the major seventh is one of two commonly occurring sevenths. It is qualified as major because it is the larger of the two.
No idea if you mean by music, but as in math:
An interval is a range of numbers between two given numbers and includes all of the real numbers between those two numbers. ... Intervals can be written using inequalities, a number line, or in interval notation!
