'onomastician' originates from Modern English formation, specifically from the adjective 'onomastic' with the agentive suffix '-ian'; 'onomastic' ultimately comes from Greek 'onomastikos', where 'onoma' meant 'name'.

'onomastician' developed by combining English 'onomastic' (from Medieval/Modern Latin onomasticus, from Greek onomastikos) with the suffix '-ian' to form a noun meaning 'one who studies names'.

Initially related to the adjective sense 'pertaining to names', the formation with '-ian' shifted the meaning to denote 'a person who studies or specializes in names'.