surface area

n. physical size of a 2-dimensional surface contained within a border, area (e.g.: The room was about 10 square meters in area")

Area is the measure of how much exposed area any two dimensional object has. It is expressed in square units, and is calculated by adding together the areas of all the faces of the object.
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Area is a physical quantity expressing the size of a part of a surface. The term Surface area is the summation of the areas of the exposed sides of an object.
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Noun
1. the extent of a 2-dimensional surface enclosed within a boundary; "the area of a rectangle"; "it was about 500 square feet in area"
(synonym) area, expanse
(hypernym) extent
(hyponym) acreage, land area

The airspace contained by the lateral boundary of the Class B, C, D, or E airspace designated for an airport that begins at the surface and extends upward.