A double-sided sword is commonly referred to as a "double-edged sword" or a "two-edged sword." This type of sword features a blade with two cutting edges, allowing for strikes and cuts from either side of the blade.

Double-edged swords have been used throughout history in various cultures and time periods. They can come in different forms and designs depending on the specific cultural context. Some examples of double-edged swords include:

• European Longsword: The European longsword, also known as a "hand-and-a-half sword" or "bastard sword," is a versatile sword with a longer blade and a hilt that can be used with one or both hands. It features a double-edged blade designed for both thrusting and cutting techniques.
• Chinese Jian: The Chinese Jian is a traditional double-edged sword with a straight, slender blade. It is known for its precise and fluid movements, often associated with Chinese martial arts and historical swordsmanship.
• Japanese Ken: While most Japanese swords, such as the katana, are single-edged, there are some double-edged Japanese swords called "ken." The ken is a straight-bladed sword used in different historical periods in Japan.

It's worth noting that the term "double-edged sword" is also used metaphorically to describe a situation or decision that has both positive and negative consequences. In this context, it refers to something that can be both beneficial and problematic at the same time.