'syntheticity' originates from an English formation that adds the Latin/French-derived suffix '-ity' to 'synthetic', which ultimately comes from Greek 'synthētikos', where 'syn-' meant 'together' and 'tithenai' meant 'to place'.

'synthetic' was borrowed into Late Latin as 'syntheticus' from Greek 'synthētikos' and entered English (via Middle/Modern Latin and French influence); the noun 'syntheticity' was later formed in Modern English by attaching the suffix '-ity' to 'synthetic'.

Initially, the Greek root conveyed the idea of 'putting together' or 'composition'; over time the derived English terms shifted to denote 'artificially made' or 'produced by synthesis', and 'syntheticity' now denotes that quality or state.