Meaning

noun an outlying farm building for storing grain or animal feed and housing farm animals

noun (physics) a unit of nuclear cross section; the effective circular area that one particle presents to another as a target for an encounter

originFrom Middle English barn, bern, bærn, from Old English bearn, bern, contracted forms of Old English berern, bereærn (“barn, granary”), compound of bere (“barley”) and ærn, ræn (“dwelling, barn”), from Proto-West Germanic *raʀn, from Proto-Germanic *razną (compare Old Norse rann), from pre-Germanic *h₁rh̥₁-s-nó-, from Proto-Indo-European *h₁erh₁- (“to rest”). More at rest and barley. For the use…

Etymology from Wiktionary, CC BY-SA 3.0