|1.||maths a plane surface formed by cutting across a solid, esp perpendicular to its longest axis|
|2.||a section cut off in this way|
|3.||the act of cutting anything in this way|
|4.||a random selection or sample, esp one regarded as representative: a cross section of the public|
|5.||surveying a vertical section of a line of ground at right angles to a survey line|
|6.||physics a measure of the probability that a collision process will result in a particular reaction. It is expressed by the effective area that one participant presents as a target for the other|
In particle physics, an expression of the probability of the occurrence of an event, typically the scattering of subatomic particles, over a given area.