Is an interval the difference between pitch between 2 tones?

"Interval" has so many meanings. It could mean an interval between two times.

In music, when relating to pitch, it is NOT the difference.

It is the RATIO.

Difference is a simple subtraction.

Yet in music the same interval is given to any two pitches with the same RATIO of frequencies.

Hence the interval between C and E is a THIRD.

the interval between G and B is also a third yet the difference in the pitch is a lot greater than the difference between C and E.

The ratio of the frequencies C / E is the same as the ratio B/G

Yes. But 'interval' is a term mainly used in music rather than physics.

The interval between 2 notes depends on the *ratio* of their frequencies (not on subtracting one frequency from the other).

For example if one frequency is double another, we say the interval between the notes is one octave.

Intervals have special names depending where the notes are in a musical scale.

BEWARE. The word 'tone' has two meanings. It can mean a frrequency. And it used for the name of a certain interval! For example the interval from C to D is a 'whole tone'. The interval from C to C# is a semitone.

You have it backwards. A tone is the difference between two different pitches, i.e. an overtone. An interval would be the from one pitch to another.

An overtone is a pretty cool phenomenon where you play two pitches at the same time but out of no where, you start hearing a third pitch even though there are two pitches playing.