a surcoat or tabard embroidered with heraldic devices, worn by medieval knights over their armor.
2.
a heraldic achievement of arms.
Origin
1325-75;Middle English; parallel to Frenchcotte d'armes
Examples from the web for coat of arms
The king awarded him a coat of arms embellished with two cinnamon sticks, three nutmegs and twelve cloves.
British Dictionary definitions for coat of arms
coat of arms
noun
1.
the heraldic bearings of a person, family, or corporation
2.
a surcoat decorated with family or personal bearings
Word Origin and History for coat of arms
n.
mid-14c., originally a tunic embroidered with heraldic arms (worn over armor, etc); see from coat (n.) + arm (n.2) and cf. Old French cote a armer. Sense transferred to the heraldic arms themselves by 1560s. Hence turncoat, one who put his coat on inside-out to hide the badge of his loyalty.