Groups of eight (6)
'groups of eight' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for octets that I've seen before include "groups of eight, say singers" , "Sets of eight" , "Groups of eight peformers" , "Groups of eight, often singers" .)
'groups of eight' is the definition.
(an octad is a group of eight things)
This is the entire clue.
(Another definition for octads that I've seen is " Groups of eight".)