barn1
n.
- a large farm building used for storage or for housing livestock.
- N. Amer. a large shed for storing road or railway vehicles.
Etymology
OE bern, berern, from bere ‘barley’ + ern, ærn ‘house’.
barn2
n.
Physics a unit of area, 10
-28 square metres, used especially in particle physics.
Etymology
1940s: appar. from the phr. as big as a barn door.
