Plain English Meaning

A storage tank that holds hydraulic fluid under pressure, ready to deliver an extra burst of power when the system needs it or to keep things working briefly if the pump fails.

Full Definition

A pressure vessel in a hydraulic system that stores fluid under pressure, typically using a compressed gas (usually nitrogen) on one side of a piston, diaphragm, or bladder, and hydraulic fluid on the other. It supplements pump output during high demand, absorbs pressure surges, and provides a reserve of pressurized fluid for emergency use or when the pump is not running.

Context Anchor

Seen in aircraft hydraulic system descriptions, landing gear and brake system discussions, and some emergency system .