Shields are used to intercept specific attacks, whether from close-ranged weaponry like spears or long ranged projectiles such as arrows. They function as means of active blocks, as well as to provide passive protection by closing one or more lines of engagement during combat.
shield noun 1. protection, cover, defence, screen, guard, ward (archaic), shelter, safeguard, aegis, rampart, bulwark innocents used as a human shield against attack 2. buckler, escutcheon (Heraldry), targe (archaic) a warrior with sword and shield