cross section

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A section formed by a plane cutting through an object, usually at right angles to an axis.
• noun A piece so cut or a graphic representation of such a piece.
• noun Physics A quantity, measured in units of barns, used to express the probability of an encounter between particles over a given area in a collision.
• noun Statistics A sample meant to be representative of a whole population.
• noun Informal A variety; a diversity.

from The Century Dictionary.

• noun A section of something made by a plane passed through it at right angles to one of its axes, especially to its longest axis; a piece of some body cut or sliced off in a direction perpendicular to an axis of the body: as, a cross-section of a tree cut out to show the grain; a drawing of the cross-section of a ship.
• noun The area of a section, of a bar, tube, rod, or other body, taken at right angles to its axis.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb to create one or a series of cross sections{3} by cutting (an object) into thin slices.
• noun a flat plane cutting through a three-dimensional object, usually at right angles to the longest axis of the object.
• noun any visual representation of a cross section{1}, showing the internal structure of the object in the plane of the cross section.
• noun a thin slice of an object made by cutting it transversely.
• noun a representative sample of a complex group.
• noun (Physics) a measure of the probability that a nucleus will interact in a specified way with a bombarding particle, expressed as the effective area that the nucleus presents to the particle; -- called also nuclear cross section.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A section formed by a plane cutting through an object, usually at right angles to an axis.
• noun statistics A sample meant to be representative of a whole population.
• noun physics The probability that a particular nuclear reaction will take place.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective representing a plane made by cutting across something at right angles to its length
• noun a section created by a plane cutting a solid perpendicular to its longest axis
• noun a sample meant to be representative of a whole population
• noun (physics) the probability that a particular interaction (as capture or ionization) will take place between particles; measured in barns