"Subdivision" means:
(a) The division of any parcel of land into two or more parcels, sites or lots; or
(b) The development of one or more parcels of land for multi-family uses or any use other than a residential use or an improvement involving the division or allocation of land for street opening, widening or extension, the division or allocation of land as open space for common use by owners, occupants or leaseholders, or an easement for extension and maintenance of sewer, water, drainage and other public facilities.