A coat of arms is a heraldic visual design on an escutcheon (i.e., shield), surcoat, or tabard (the last two being outer garments).

The coat of arms on an escutcheon forms the central element of the full heraldic achievement, which in its whole consists of a shield, supporters, a crest, and a motto.

A coat of arms is traditionally unique to the armiger (e.g. an individual person, family, state, organization, school or corporation). The term "coat of arms" itself, describing in modern times just the heraldic design, originates from the description of the entire medieval chainmail "surcoat" garment used in combat or preparation for the latter.