A word that seems to have been interchangeable meaning a cote armour blazoned with a device, or a surcoat bearing the heraldic charge of a man's affiliation. Because it was the most visible expression of a knight's arms, the word has come to mean the heraldic device itself rather than the cote upon which it was sewn, painted, or embroidered.
COTE OF ARMS
Meaning of COTE OF ARMS in English
Medieval English glossary. Средневековый английский глоссарий. 2012