'arborescentness' originates from Latin, specifically the word 'arbor', where 'arbor' meant 'tree', combined with the Latin suffix '-escens' (from 'escēns') meaning 'becoming' (forming the adjective 'arborescent'), and the English noun-forming suffix '-ness' which creates a quality or state.

'arborescentness' developed from Latin 'arbor' → Late Latin/Medieval Latin 'arborescens' (meaning 'becoming tree-like') → adopted into English as the adjective 'arborescent' in the modern period, with the noun-forming suffix '-ness' later appended to create 'arborescentness'.

Initially rooted in the idea 'becoming tree-like' (the sense of the adjective 'arborescent'), it evolved to denote specifically the noun 'the quality or condition of being tree-like'.