cross section

¹ American  

[kraws sek-shuhn, kros] / ˈkrɔs ˌsɛk ʃən, ˈkrɒs /

noun

1. a section made by a plane cutting anything transversely, especially 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. Surveying. 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.

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cross-section ² American  

[kraws-sek-shuhn, kros-] / ˈkrɔsˈsɛk ʃən, ˈkrɒs- /

adjective

1. Also cross-sectional. of or relating to a cross section.

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verb (used with object)

1. to make or divide into a cross section.

cross section British  

noun

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

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cross section Scientific  

1. In particle physics, an expression of the probability of the occurrence of an event, typically the scattering of subatomic particles, over a given area.

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Other Word Forms

• cross-sectional adjective

Etymology

Origin of cross section¹

First recorded in 1825–35

Origin of cross-section²

First recorded in 1875–80

Example Sentences

However, the scenario has prompted a cross section of the typically fractious party to unite behind the belief the field must shrink, whether by candidates’ choice or through pressure.

From Los Angeles Times • Feb. 21, 2026

The American middle class encompasses a broad cross section of workers that includes white-collar office employees, nurses and plumbers, although there is no universally accepted definition.

From The Wall Street Journal • Nov. 21, 2025

“These days we’ve got a truly diverse cross section of South Africa coming to the event, all ages, races, and genders,” says rAge project director, Michael James.

From BBC • Sep. 2, 2024

Some models predict that dark matter has a certain mass or cross section, which is the probability of a specific event occurring due to the interaction of particles.

From Science Daily • Mar. 20, 2024

We had them all facing the same way so that their shadows on the wall looked like a computer rendering of an architectural cross section.

From "The View From Saturday" by E.L. Konigsburg

Related Words

• random sample
• sampling