Like our major and minor scales, the modes are a system of scales used most often in pretonal music (medieval and Renaissance) and 20th century music (classical, jazz, and rock). The history of modes is a rich, confusing story and reaches all the way back to ancient Greece. But, for now, we only need the basics for our current use in counterpoint.
In music before the tonal era, composers and theorists talked about six modes: Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Ionian. And mostly used the white-note (accidental-less) versions. Since the 20th century, we can add Locrian and also transpose them to begin on any pitch.
- Ionian (Major): C to C
- Dorian (Minor + raised 6 [La]): D to D
- Phrygian (Minor + lowered 2 [Ra]): E to E
- Lydian (Major + raised 4 [Fi]): F to F
- Mixolydian (Major + lowered 7 [Te]): G to G
- Aeolian (Minor): A to A
- Locrian (Minor + lowered 2 [Ra] + lowered 5 [Se]): B to B