Plain English Meaning
The different kinds of instrument approaches a pilot can fly using GPS or other area navigation, instead of approaches built around ground stations like an ILS or VOR. Each type has different equipment requirements and different minimum altitudes the pilot can descend to.
Full Definition
The category of instrument approach procedures that use Area Navigation (RNAV) for lateral guidance, allowing aircraft to fly point-to-point courses defined by waypoints rather than tracking signals from ground-based navigation aids. The principal RNAV approach types are , stand-alone GPS approaches, (GPS) approaches with , , LP, and lines, and RNAV (RNP) approaches that require aircraft and authorization.