ZONE (3)

Zone, n. 1. 1. (Biogeography) An area or part of a region characterized by uniform or similar animal and plant life; a life zone; as, Littoral zone, Austral zone, etc. The zones, or life zones, commonly recognized for North America are Arctic, Hudsonian, Canadian, Transition, Upper Austral, Lower Austral, and Tropical.
2. 2. (Cryst.) A series of faces whose intersection lines with each other are parallel.
3. 3. (Railroad Econ.) (a) The aggregate of stations, in whatsoever direction or on whatsoever line of railroad, situated between certain maximum and minimum limits from a point at which a shipment of traffic originates. (b) Any circular or ring-shaped area within which the street-car companies make no differences of fare.
4. 4. In the United States parcel-post system, any of the areas about any point of shipment for which but one rate of postage is charged for a parcel post shipment from that point. The rate increases from within outwards. The first zone includes the unit of area “(a quadrangle 30 minutes square)” in which the place of shipment is situated and the 8 contiguous units; the outer limits of the second to the seventh zones, respectively, are approximately 150, 300, 600, 1000, 1400, and 1800 miles from the point of shipment; the eighth zone includes all units of area outside the seventh zone.