Massachusetts General Law Chapter 41 Section 81L defines a "Subdivision", as follows:
"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 way which the clerk of the city or town certifies is maintained and used as a public way, or (b) a way shown on the 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 abuttting thereon or served thereby, and for the installation of municipal services to serve such land and the buildings erected or to be erected thereon". (MGL C. 41, S. 81L )
In layman terms a "subdivision" can also be interpreted to mean a division of a parcel of land into two or more lots, so that every lot within the tract of land so divided obtains adequate frontage and access on a way of adequate construction to accommodate the vehicular traffic relative to the proposed use of the land, the installation of municipal services (i.e. water, sewerage, gas, electricity), and number of building lots.
Form A (also referred to as an ANR Plan) is the division of a tract of land into two or more lots, whereby every lot within the tract so divided (a) has frontage on an acceptable way as specified in MGL C.41, S. 81L, (b) meets the minimum frontage requirement required by zoning for the district, and (c) is determined by the Planning Board to have vital access to the buildable portion of the lots.