'arboroid' originates from Latin, specifically the word 'arbor', where 'arbor' meant 'tree', combined with the Greek-derived suffix '-oid' (from Greek 'eidos') meaning 'form' or 'likeness'.

'arboroid' entered English as a scholarly/scientific formation in Neo-Latin/late-modern coinage combining Latin 'arbor' + suffix '-oid', and eventually became the English adjective 'arboroid'.

Initially the components meant 'tree' (from 'arbor') and 'form/likeness' (from '-oid'), and over time the compound came to mean specifically 'having a tree-like or branching form'.