🏚️ A farm building ⚛️ A tiny unit

barn

7 9.6

A very small unit of area used in nuclear physics equal to 10⁻²⁸ square meters

noun
/bɑrn/

Specialized

: barn

In nuclear physics, a proton's effective cross-sectional area can be measured in units called barn.

Examples

The cross-section for this nuclear reaction is about fifteen barns.
He was also a breeder of fine racehorses, some of which were housed in the Rock Barn, making it an appropriate place for the Derby Day festivities.

Academic text (2013)
Henry, come with me to the barn to check on the horses.

Fiction book (1999)
"And the rich man said I will pull down my barns, "and build greater..."

First Reformed (2018)
"I don't know," Lettie yelled back as she ran to the barn to lead the horses closer to the house.

Fiction book (1990)
Researchers often express the size of nuclear interactions in barns to simplify calculations.

Synonyms

vsbarn

Specialized

9.9

A very small unit for measuring area in nuclear physics equal to 10⁻²⁸ square meters

is the physical cross-sectional area measure of atomic nuclei

Idioms

born in a barn

Offensive

9.9

To act carelessly or rudely, for example leaving doors open

around Robin Hood's barn

9.9

To take a long, unnecessary route to reach a place or answer

to smell the barn

Informal

9.7

To feel the end of a trip or task is near

Compounds

barn door

5 1.0

A large door at the front of a barn for moving animals and farm goods

barn dance

3 3.6

A party in a barn where people dance country dances

cow barn

1 1.2

A barn where cows are kept for shelter or milking

barn owl

1 2.6

A medium-sized owl with pale, spotted feathers that lives in barns and eats mice

horse barn

1 1.5

A building on a farm where people keep horses

barn swallow

1 3.7

A small bird with a long forked tail that builds nests in barns and on farms

barn find

Jargon

7.7

A valuable old thing, often a car, that someone finds forgotten in a barn

barn grass

8.3

A common weed grass that farmers sometimes cut for hay or feed animals

barn millet

9.8

A coarse grass that grows each year, often seen as a weed and used for hay or grazing

barn spider

5.5

A large orange and tan spider often found in barns that makes a new round web each day

tithe barn

Archaic

9.9

A barn where farmers give part of their crops to the church

Surface Forms

barn singular

barns plural

Etymology

Barn (the physics unit) was named as a joke by 1940s scientists who used the saying 'can't hit the broad side of a barn' to mean a big target. They called a very small nuclear area a barn, and that name stuck, so barn is now the unit for tiny nuclear areas.