It is considered that the name of seven-pronged sword was derived from the shape of sword which looks like a halberd and has seven blades in total; From the right and left sides of the main body, three branch blades stick out respectively.
七支刀（しちしとう）の名は、鉾に似た主身の左右から三本ずつの枝刃を出して計て七本の刃を持つ形に由来すると考えられる。