53 Pa. C.S. § 712
The following words and phrases when used in this subchapter shall have the meanings given to them in this section unless the context clearly indicates otherwise:
"Abutting municipal corporations." Municipal corporations that share contiguous territory.
"Boundary ascertainment." Establishment of a municipal boundary between abutting municipal corporations by judicial decree.
"Boundary change" or "change of boundary." Any change in the municipal boundary between abutting municipalities, other than as a result of a merger or consolidation under Subchapter C (relating to consolidation and merger), including any transfer of territory, boundary clarification or boundary ascertainment.
"Boundary clarification." Establishment of a municipal boundary by agreement under this subchapter between municipal corporations in a territorial area with a previously unclear boundary.
"Contiguous territory." Territory of which a portion abuts the boundary of another municipal corporation, including territory separated from the exact boundary of another municipal corporation by a street, road, railroad or highway or by a river or other natural or artificial stream of water.
"Governing body." The council in a city, borough or incorporated town, the board of commissioners in a county or township of the first class, the board of supervisors in a township of the second class or the legislative policymaking body in a home rule municipality.
"Impacted property." A parcel of real property that is divided by a municipal boundary prior to, or will be divided incident to, a proposed boundary change.
"Impacted territory." Territory which is subject to a boundary change.
"Municipal corporation." A city, borough, incorporated town, township or home rule municipality that is not a county.
"Municipality." A county, city, borough, incorporated town or township.
"Unclear boundary." Contiguous territory between two municipal corporations in which the exact boundary between the municipal corporations is in dispute or cannot be readily discerned as a result of conflicting or missing records.
53 Pa.C.S. § 712