For the purpose of this subchapter the term “subdivision” means the division of a parcel of land into 4 or more lots or parcels for the purpose of transfer of ownership or building development, or, if a new street is involved, any division of a parcel of land. Any division of land for agricultural purposes into lots or parcels of 5 acres or more and not involving a new street shall not be deemed a subdivision. The term shall include resubdivision and, when appropriate to the context shall relate to the process of subdividing or to the land subdivided.