Diatonic Modes. There are seven Diatonic Modes in a scale and they are Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian and Locrian.
Sounds hard right? - It's not!
Check it out! In the key of C Ionian goes from C to C. Dorian goes from D to D and so on so whats happening is the half and whole steps are being shifted for each Mode and thats all there is to it.
We can think of the notes as numbers the 1 to the 1 is Ionian and the 2 to the 2 is Dorian the 3 to the 3 is Phrygian and so on.
Please have a look at Diatonic Harmony to see why I think the numbers way is cooler.
Check out this fast 5 question music theory test.