expanse (
http://definr.com/expanse)
n 1: a wide scope; "the sweep of the plains" [syn:
sweep]
2: the extent of a 2-dimensional surface enclosed within a
boundary; "the area of a rectangle"; "it was about 500
square feet in area" [syn:
area,
surface area]
3: a wide and open space or area as of surface or land or sky