1. a section made by a plane cutting anything transversely, esp. at right angles to the longest axis.
2. a piece so cut off.
3. a photograph, diagram, or other pictorial representation of such a section.
4. the act of cutting anything across.
5. a typical selection; a sample showing all characteristic parts, relationships, etc.: a cross section of American opinion.
6. Survey.a vertical section of the ground surface taken at right angles to a survey line.
7. Also called nuclear cross section. Physics.a quantity expressing the effective area that a given nucleus presents as a target to a bombarding particle, giving a measure of the probability that the particle will induce a reaction.
Pronunciation: (krôs'sek'shun, kros'-), [key]
Also,cross'-sec'tion•al.of or pertaining to a cross section.
to make or divide into a cross section.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.