'armful' originates from Old English, specifically the word 'earm' (meaning 'arm') combined with the suffix 'ful' from Old English 'ful' (meaning 'full' or 'full of').

'armful' changed from Old English word 'earmful' (literally 'arm-full') and through Middle English became the modern English word 'armful'.

Initially it meant 'a quantity that fills the arm' and over time the meaning has remained largely the same, used for any amount one can hold in the arms.