2 Geology of, relating to, or denoting the later part of the Carboniferous period in North America, following the Mississippian and preceding the Permian, and corresponding to the Upper Carboniferous of Europe. This period lasted from about 323 to 290 million years ago.
noun
1a native or inhabitant of Pennsylvania.
2 (the Pennsylvanian) Geology the Pennsylvanian period or the system of rocks deposited during it.
