a section made by a plane cutting anything transversely, especially at right angles to the longest axis.
a photograph, diagram, or other pictorial representation of such a section.
the act of cutting anything across.
a typical selection; a sample showing all characteristic parts, relationships, etc.:
a cross section of American opinion.
Surveying. a vertical section of the ground surface taken at right angles to a survey line.
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.