Plain English Meaning

It's an old-style approach built around a ground radio beacon, but you're allowed to fly it using your GPS instead of tuning that beacon. The path and altitudes are the same — only the equipment guiding you down is different.

Full Definition

An instrument approach procedure originally designed for ground-based navigation aids (such as VOR, NDB, or TACAN) that has been authorized for flight using GPS or RNAV equipment in place of the underlying navaid. The approach retains its original name and ground-based design, but the pilot navigates the same course, fixes, and altitudes using approved equipment.