'apartado' originates from Spanish, specifically formed from the verb 'apartar' plus the participle suffix '-ado'. The root 'apart-' comes from Vulgar Latin/Old French elements meaning 'away' or 'separate' (from Latin 'ad' + 'partem' meaning 'to/part').

'apartado' developed in Spanish as the past participle/adjectival form of 'apartar', which itself derives from earlier Romance formations (Old Spanish/aparte < Vulgar Latin *aparte < Latin components 'ad' + 'partem'). Over time the participle form stabilized as the modern Spanish adjective/noun 'apartado'.

Initially it denoted 'made separate' or 'set apart' (the literal past-participle sense); over time it also acquired noun senses such as 'section' of a text and the specialized postal meaning 'P.O. box'.