Knight, in the Middle Ages, a warrior horseman. A knight was called Sir, and was usually of a noble or a genteel family. Knighthood, however, was not inheritedit had to be earned by many years of training. Besides a sword and a shield, a knight in combat might carry a battle-ax, mace, or lance. Early in the Middle Ages his armor consisted of a chain mail tunic and a helmet, but by the end of the Middle Ages the knight was encased in sheet-metal armor from head to foot.
The present-day title of knight is an honor given to persons who have achieved distinction in their work.