The following words and phrases when used in this chapter shall have the meanings given to them in this section unless the context clearly indicates otherwise:
"Improving a street." The term includes work upon a street or portion thereof done or proposed to be done in order to open the street, if the street has not previously been opened or, if previously opened, to make the street more usable or more suitable for use by the traveling public or safer for the use. The term includes, but is not limited to, grading, paving, curbing and macadamizing.
"Laying out." The term includes the plotting of:
"Opened streets." The term includes the streets within the borough used as public passageways.
"Opening a street." The term includes the construction and grading of a street or portion thereof and the act of physically taking possession of an area or laid-out street for the purpose of making the same usable to the traveling public.
"Person." The term includes a natural person, association, firm, corporation or political subdivision.
"Personal notice." The term includes notice upon the owner of a premises either by personal service upon the owner or by certified mail to the owner at the owner's last known address. Where service has not been successfully made by either of the two methods first mentioned, it may be made by leaving the notice at or upon the premises.
"Portion." The term includes a portion either of the width or length of a street. Opening a portion of a street may mean extending or widening a street and vacating a portion of a street may mean closing or narrowing a street.
"Street." The term includes a street, road, lane, court, cul-de-sac, alley, public way and public square, either for or intended for public use, and includes the cartway, sidewalk, gutter and the right-of-way area, whether or not the street or a part of the street is owned in fee by others than the borough. Streets are of two classes, opened and unopened.
"Unopened streets." The term includes the streets within the borough neither used as a public passageway, nor accepted ormaintained, but plotted in one of the following:
8 Pa.C.S. § 1701