Section 81L. In construing the subdivision control law, the following words shall have the following meaning, unless a contrary intention clearly appears:—

''Applicant'' shall include an owner or his agent or representative, or his assigns.

''Certified by [or endorsed by] a planning board'', as applied to a plan or other instrument required or authorized by the subdivision control law to be recorded, shall mean, bearing a certification or endorsement signed by a majority of the members of a planning board, or by its chairman or clerk or any other person authorized by it to certify or endorse its approval or other action and named in a written statement to the register of deeds and recorder of the land court, signed by a majority of the board.

''Drainage'', shall mean the control of surface water within the tract of land to be subdivided.

''Lot'' shall mean an area of land in one ownership, with definite boundaries, used, or available for use, as the site of one or more buildings.

''Municipal service'' shall mean public utilities furnished by the city or town in which a subdivision is located, such as water, sewerage, gas and electricity.

''Planning board'' shall mean a planning board established under section eighty-one A, or a board of selectmen acting as a planning board under said section, or a board of survey in a city or town which has accepted the provisions of the subdivision control law as provided in section eighty-one N or corresponding provisions of earlier laws, or has been established by special law with powers of subdivision control.

''Preliminary plan'' shall mean a plan of a proposed subdivision or resubdivision of land drawn on tracing paper, or a print thereof, showing (a) the subdivision name, boundaries, north point, date, scale, legend and title ''Preliminary Plan''; (b) the names of the record owner and the applicant and the name of the designer, engineer or surveyor; (c) the names of all abutters, as determined from the most recent local tax list; (d) the existing and proposed lines of streets, ways, easements and any public areas within the subdivision in a general manner; (e) the proposed system of drainage, including adjacent existing natural waterways, in a general manner; (f) the approximate boundary lines of proposed lots, with approximate areas and dimensions; (g) the names, approximate location and widths of adjacent streets; (h) and the topography of the land in a general manner.

''Recorded'' shall mean recorded in the registry of deeds of the county or district in which the land in question is situated, except that, as affecting registered land, it shall mean filed with the recorder of the land court.

''Register of deeds'' shall mean the register of deeds of the county or district in which the land in question, or the city or town in question, is situated, and, when appropriate, shall include the recorder of the land court.

''Registered mail'' shall mean registered or certified mail.

''Registry of deeds'' shall mean the registry of deeds of the county or district in which the land in question is situated, and, when appropriate, shall include the land court.

''Subdivision'' shall mean the division of a tract of land into two or more lots and shall include resubdivision, and, when appropriate to the context, shall relate to the process of subdivision or the land or territory subdivided; provided, however, that the division of a tract of land into two or more lots shall not be deemed to constitute a subdivision within the meaning of the subdivision control law if, at the time when it is made, every lot within the tract so divided has frontage on (a) a public way or a way which the clerk of the city or town certifies is maintained and used as a public way, or (b) a way shown on a plan theretofore approved and endorsed in accordance with the subdivision control law, or (c) a way in existence when the subdivision control law became effective in the city or town in which the land lies, having, in the opinion of the planning board, sufficient width, suitable grades and adequate construction to provide for the needs of vehicular traffic in relation to the proposed use of the land abutting thereon or served thereby, and for the installation of municipal services to serve such land and the buildings erected or to be erected thereon. Such frontage shall be of at least such distance as is then required by zoning or other ordinance or by-law, if any, of said city or town for erection of a building on such lot, and if no distance is so required, such frontage shall be of at least twenty feet. Conveyances or other instruments adding to, taking away from, or changing the size and shape of, lots in such a manner as not to leave any lot so affected without the frontage above set forth, or the division of a tract of land on which two or more buildings were standing when the subdivision control law went into effect in the city or town in which the land lies into separate lots on each of which one of such buildings remains standing, shall not constitute a subdivision.

''Subdivision control'' shall mean the power of regulating the subdivision of land granted by the subdivision control law.