'barnful' originates from Old English, specifically the element 'barn' (from Old English elements 'bere' meaning 'barley' and 'ærn' meaning 'house') combined with the suffix '-ful' from Old English 'full' meaning 'full of'.

'barnful' developed in Middle English as a compound of 'barn' and the suffix '-ful' and eventually became the modern English word 'barnful'.

Initially, it meant 'an amount that fills a barn', and over time this core meaning has remained largely unchanged.