"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 efficient because it utilizes both sides of the piston, making it ideal for various applications, such as in hydraulic systems and air compressors. In a broader sense, double-acting can also apply to other systems, like pumps or cylinders, where the action occurs in two phases. This dual-action capability enhances performance and productivity, making double-acting systems popular in industrial and mechanical engineering.