Half a score (6)
'half a score' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ten that I've seen before include "honour" , "How many" , "Dudley Moore/Bo Derek film" , "X-WORD" , "Base of decimal system" .)
'half a score' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for decade that I've seen before include "Time period" , "Ten-year span" , "Period of ten years" , "The 1960s, for example" , "Ten-year period" .)