cross section also cross-sec·tion (krôs'sěk'shən, krŏs'-) n.
A section formed by a plane cutting through an object, usually at right angles to an axis.
A piece so cut or a graphic representation of such a piece.
Physics A measure of the probability that an encounter between particles will result in the occurrence of a particular atomic or nuclear reaction. Also called collision cross section.
Statistics A sample meant to be representative of a whole population.
