Naphtha

A volatile and flammable hydrocarbon liquid used chiefly as a solvent or as a cleaning fluid.

Aviation Maintenance Technician Handbook — Airframe, p. G-23

Also defined in 1 more source

A volatile, flammable liquid distilled from petroleum. It is used as a cleaning agent and solvent, and is present in some blended turbine-engine fuels.

Aviation Maintenance Technician Handbook — Powerplant, p. G-18