'appress' originates from Latin, specifically the verb 'appressare', where the prefix 'ad-' (in form 'ap-') meant 'toward' and 'pressare' (from 'premere') meant 'to press'.

'appress' changed from Old French 'appresser' and Middle English 'appressen' and eventually became the modern English verb 'appress' (with the past/past-participle form 'appressed').

Initially, it meant 'to press toward (something)', but over time it evolved into the modern sense 'to press closely or lie flat against', especially in descriptive biology contexts.