Arab manuscript's insignia
I believe the answer is:
arms
'insignia' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'arab manuscript's' is the wordplay.
'arab' becomes 'ar' (abbreviation in Chambers).
'manuscript's' becomes 'ms'' ('ms' can be a synonym of 'manuscript').
'ar'+'ms'='ARMS'
Can you help me to learn more?
(Other definitions for arms that I've seen before include "International competition for weapons" , "Guns et cetera" , "George Bernard Shaw play '. . . . and the Man'" , "pacifists won't take up" , "military equipment" .)