"Double-acting" refers to a mechanism that can perform work in both directions. In the context of a piston, for example, a double-acting piston can push and pull, allowing it to generate force during both the upward and downward strokes. This design is commonly used in hydraulic systems and pneumatic tools, making them more efficient and powerful. In a double-acting cylinder, fluid pressure is applied to both sides of the piston. This means that when the fluid enters one side, it pushes the piston in one direction, and when it enters the other side, it pushes the piston back. This capability enhances the performance of machines, such as excavators and compressors, by providing consistent power and speed.