'applicator' originates from Latin, specifically the word 'applicare', where 'ad-' meant 'to/toward' and 'plicare' meant 'to fold' or 'to join/attach'.

'applicare' (Latin) gave rise to Medieval/Religious Latin forms and English formations; the agent noun was formed with the suffix '-ator' to create 'applicator', which entered English usage from Neo-Latin or technical formation.

Initially it referred to 'one who or that which attaches or applies' in a general sense; over time it has come to refer more specifically to devices or tools used to apply substances or to instruments for precise delivery.