Short saying (7)
(Other definitions for motto that I've seen before include "Part of coat of arms" , "device" , "Words often found on coat of arms" , "Phrase in a Christmas cracker" , "Saying; slogan" .)
'short saying' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for proverb that I've seen before include "Traditional saying" , "OT saying" , "Well-known statement incorporating general truth" , "Make haste slowly, perhaps" , "Maxim" .)