Definition of Pennsylvanian
1relating to the state of Pennsylvania. 2 Geology 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.
1a native or inhabitant of Pennsylvania. 2
) Geology the Pennsylvanian period or the system of rocks deposited during it.