Definition
A device that converts the energy of pressurized hydraulic fluid into rotary mechanical motion, producing torque at an output shaft to drive a load. It is essentially the reverse of a hydraulic pump: fluid flow in produces shaft rotation out.
Plain English
A motor that is spun by pressurized fluid instead of electricity. Fluid pushed into it makes its shaft turn, which can then turn something else like a flap, winch, or pump.
Context Anchor
Seen in aircraft hydraulic system descriptions and maintenance information for parts that are powered by fluid pressure.
Derivation
Hydraulic comes from the Greek hydor meaning water, combined with aulos meaning pipe. The original sense was 'operated by water in a pipe.' In aviation, the principle is the same — pressurized fluid in a line — but the fluid is specialized hydraulic oil rather than water.
Why Pilots Care
Supplies mechanical power to essential systems without depending on electrical sources, maintaining function during electrical failures.
Intuition Check
Do not assume motor means electric motor here. A hydraulic motor is powered by pressurized fluid, not by electricity, and it produces turning motion rather than pumping fluid.
Example Sentence 1
The cargo door on the freighter is driven by a hydraulic motor powered by the number two system.
Example Sentence 2
Technicians inspected the hydraulic motor for leaks before reinstalling the landing gear actuator.