Music theory definition
Perfect interval
Unisons, 4ths, 5ths, and octaves in their natural size. They sound open and stable.
Hear an example
Play the example and listen for the idea described above.
Quality: the second half of the name
Two 3rds can differ in size, so get a .
Learn it in context
This term is introduced in Unit 5: Intervals. Work through the explanations and exercises to connect the definition with music.
- Major and perfect intervals
The intervals found above the tonic of a major scale.
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- Interval trainer
Explore every interval with sound and sight, or train your ear with the intervals you choose.
Related music terms
- Interval
- The distance between two notes, named by number (how many letters) and quality.
- Major interval
- The larger form of a 2nd, 3rd, 6th or 7th - the size found above the tonic of a major scale.
- Minor interval
- A major interval made a half step smaller.
- Augmented
- A half step larger than perfect or major.
- Diminished
- A half step smaller than perfect or minor.
- Tritone
- An interval of three whole steps (six half steps) - an augmented 4th or diminished 5th. Famously restless.