A section of a solid is the plane figure cut from the solid by passing a plane through it (Kern and Bland 1948, p. 18).

Kern, W. F. and Bland, J. R. Solid Mensuration with Proofs, 2nd ed. New York: Wiley, 1948.

CITE THIS AS:

Weisstein, Eric W. "Section." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/Section.html