A double-sided spear is commonly referred to as a "double-headed spear" or a "bisento." It is a polearm that features a spearhead or blade on both ends of the shaft. This design allows for versatile offensive and defensive techniques as the user can attack from either direction without needing to reposition the weapon.

Double-headed spears have been used in various historical periods and cultures. They were employed by ancient civilizations such as the Greeks and Romans, as well as by medieval European knights and samurai warriors in feudal Japan. The specific name for a double-headed spear may vary depending on the cultural context or region. For example, in Japan, a similar weapon called a "naginata" features a curved blade on one end and a spearhead on the other, while a "bisento" typically refers to a larger, heavy-bladed weapon with two spearheads.