'applicate' originates from Latin, specifically the word 'applicare,' where the prefix 'ap-' (from 'ad-') meant 'to/toward' and the root 'plicare' meant 'to fold' or 'to join/press together'.

'applicate' entered English via Late Latin 'applicatus' (past participle of 'applicare') and was adopted into English in technical and legal usage; over time the form stabilized as 'applicate'.

Initially, it meant 'to attach or press to' (literally to bring into contact); over time it broadened to include 'to apply (a substance), to put into operation, or to make applicable' and is now used primarily in technical or legal contexts.