'barn' originates from Old English, specifically the word 'bereærn' (also attested as 'bern'), where 'bere' meant 'barley' and 'ærn' meant 'house' or 'place'.

'barn' changed from Old English 'bereærn' / 'bern' to Middle English forms like 'berne' and eventually became the modern English word 'barn'.

Initially, it meant 'barley-house' (a place for storing barley); over time it broadened to mean a general farm building for storing grain, hay, or sheltering animals.