Cutter's sword which is longer than a box cutter but can be stored in a box because its size is not infinite.
EDIT: The sword that always beheads its owner hence the fact it is used by a headless knight who only appears in a sleepy hollow at night riding a mare to make him look even more nightmarish
The swordfish someone found in the eponymous Normandy beach hence its name unless it is because is shaped like a swordfish which would mean the beach also owes its name to the fish