Quillon refers to the projecting arms extending to either side of a sword's crossguard, which is the bar located between the blade and the hilt. These components are designed to protect the wielder's hand and fingers from opposing weapons and to prevent the hand from sliding onto the blade.
Depending on the specific style of the weapon, quillons may be straight, curved, or otherwise shaped. In certain designs, these projections serve additional functional purposes, such as catching, binding, or controlling an opponent's blade during combat.