'arbuscle' originates from Latin, specifically the word 'arbuscula', where 'arbuscula' was a diminutive of 'arbor' meaning 'tree'.

'arbuscle' came into English via Medieval/ Late Latin 'arbuscula' (and related Romance-language forms) and was used in late medieval and early modern English; it has since become rare or literary.

Initially it meant 'a little tree' in Latin; over time it retained the sense of 'small tree or shrub' but became an uncommon/archaic term in modern usage.