Music theory definition
Extension
A chord tone beyond the 7th: the 9th, 11th, or 13th.
Hear an example
Play the example and listen for the idea described above.
Beyond the seventh
Keep stacking 3rds: 9th, 11th, 13th = the .
Learn it in context
This term is introduced in Unit 16: Extended and altered harmony. Work through the explanations and exercises to connect the definition with music.
- Ninths, elevenths, thirteenths
Keep stacking thirds.
Related music terms
- Tritone substitution
- Replacing a dominant 7th with the dominant 7th a tritone away (D♭7 for G7). They share the same tritone.
- Neapolitan chord
- A major chord on the lowered 2nd degree (♭II), usually in first inversion.
- Altered chord
- A dominant chord with raised or lowered 5ths or 9ths for extra tension.