It's quite usual in heraldry (8)
I believe the answer is:
ordinary
'heraldry' is the definition.
(ordinary is a kind of heraldry)
'it's quite usual in' is the wordplay.
I cannot really see how this works, but
'in' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ordinary that I've seen before include "Normal or average" , "Not exceptional in any way" , "Common-or-garden" , "Usual - bishop in his province" , "old bicycle" .)