Is it incorrect to refer to a C-130 as a jet?
CNN actually called it a jet with four turboprop engines, if you can believe that.

ICAO is probably as universal a source as you will find. They list the C130 as turboprop/turboshaft. Their table of aircraft type designators allows selection of engine types from this list: Jet, Turboprop/turboshaft, electric, piston and rocket. There are no associated definitions.