The
hilt of a
sword refers to its handle, including the guard,
grip and pommel.
The pommel serves various purposes depending on the type of sword.
The grip can be made from anything, usually something that would provide
a sure grip, such as leather.
The guard, depending on the type of weapon, can consist of a simple
cross piece or a more elaborate cage, designed to protect the hand.
In the specific case of the
rapier, the guard usually consists
of a cup or wire cage, a crossguard (quillons) and a knuckle bow.
All of this is designed to protect the sword hand from a blow during a fight.