In the rigorous terminology of the College of Arms, Or constitutes one of the two metals (metals) alongside Argent. It serves as a visual substitute for aurum, representing sovereignty, majesty, and the sun. According to the foundational rule of tincture, Or must never be placed upon another metal, such as Argent, to ensure high aesthetic contrast and legibility on the medieval battlefield. In non-colored representations, such as engravings, the metal is indicated by a pattern of small dots or points.
Historically, the application of Or in noble armory was often a literal display of wealth, utilizing Florentine gold leaf or shell gold in illuminated grants of arms. Its presence in a coat of arms often signified a lineage of high status, reflecting the light of the soul or the permanence of the divine. During the Tudor and Stuart periods, heraldic writers further associated Or with the topaz among gemstones and the Sun among celestial bodies, reinforcing its position at the apex of the heraldic hierarchy.