The Spanish word 'acerca' meaning 'about' or 'concerning' comes from combining two Latin prepositions: 'ad' meaning 'toward' and 'circa' meaning 'around'. These two prepositions merged to form a single word that expresses the notion of being 'about' something or 'concerning' a topic, essentially describing proximity or relevance to a subject matter.

A related and simpler Spanish word is 'cerca' meaning 'near' or 'close', which comes directly from the Latin 'circa'. When you see 'acerca de' in Spanish (the complete prepositional phrase), you can think of it as metaphorically bringing you 'close to' or 'near to' the topic being discussed.

English speakers might recognize the Latin root 'circa' in several common English words. The word 'circle' comes from the same Latin root, as does 'circus', both referring to something that goes 'around'. We also use 'circa' directly in English when approximating dates, as in 'circa 1900'. The prefix 'circum-' as in 'circumference' or 'circumstance' also comes from this same Latin root.