The side of a sword is commonly referred to as the "edge" of the blade. The edge is the sharpened portion of the blade that is used for cutting or slicing. It runs along the length of the blade and is typically located opposite the back or spine of the sword.

When referring to the edge, it is important to distinguish between the primary edge and the secondary edge, if applicable. In most swords, such as a katana or a European longsword, there is a single primary edge that runs along one side of the blade. However, some swords, such as certain types of Chinese dao, may feature a second cutting edge on the opposite side of the blade, referred to as a secondary edge.

It is worth noting that the edge of a sword is usually the sharp and vulnerable part, requiring caution when handling to prevent accidental cuts or injuries.