In the specialized vocabulary of the College of Arms and the medieval historian, 'mail' strictly refers to flexible armor formed by the intricate interlacing of hand-forged iron or steel rings. Each ring was typically pierced by a small rivet to prevent the link from expanding under the force of a weapon's impact. This construction provided high mobility compared to later plate defenses, though it was often worn over a padded gambeson to absorb the kinetic energy of blunt force trauma. In the context of the English nobility, the quality of one's mail—often featuring latten borders or gilded links—served as a visible marker of status and knightly rank during the high feudal period.
Within heraldry, mail is frequently depicted in the representation of 'armoured' crests or supporters, often blazoned as 'proper.' For the Garter King of Arms, the acquisition of a full suit of mail was not merely a military necessity but a significant capital investment, often costing more than a small freehold estate. This financial threshold solidified the divide between the landed gentry and the common soldiery. During the transition to the 14th century, mail was gradually supplemented by plate, eventually being relegated to 'gussets' or 'voiders' designed to protect joints not covered by solid steel, yet it remained a symbol of the quintessential 'miles' or knight in both art and law.