/ap'euh lay"chee euh, -cheuh, -lach"ee euh, -lach"euh/ , n.
1. Geol. a Paleozoic landmass, the erosion of which provided the sediments to form the rocks of the Appalachian Mountains.
2. a region in the E United States, in the area of the S Appalachian Mountains, usually including NE Alabama, NW Georgia, NW South Carolina, E Tennessee, W Virginia, E Kentucky, West Virginia, and SW Pennsylvania.