harmonic progression
Concise Oxford English Dictionary © 2008 Oxford University Press:
harmonic progression
▶noun
- 1 Music a series of chord changes forming the underlying harmony of a piece of music.
- 2 Mathematics a sequence of quantities whose reciprocals are in arithmetical progression (e.g. 1,
,1/ 3 ,1/ 5 , etc.).1/ 7
'harmonic progression' also found in these Oxford entries:

