Any of various devices that convert the energy in a stream of fluid into mechanical energy by passing the stream through a system of fixed and moving fanlike blades and causing the latter to rotate.
A turbine looks like a large wheel with many small radiating blades around its rim. There are four broad classes of turbine: water (hydraulic), steam, wind, and gas. The most important application of the first three is the generation of electricity; gas turbines are most often used in aircraft.