They're smaller than eighths (6)
I believe the answer is:
ninths
(Other definitions for ninths that I've seen before include "Intervals of just over an octave" , "There are 7 of these parts in 63, say" .)
I've seen this clue in the Universal.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free.
Check out my app
or
learn more
about the Crossword Genius project.