'frontier-themed' originates from Modern English, combining the noun 'frontier' and the participial adjective-forming element '-themed' derived from the noun 'theme' (ultimately from Greek 'thema' via Latin).

'frontier' changed from Old French 'frontiere' (Medieval Latin influence) into Middle English 'frontier' and then the Modern English 'frontier'; 'theme' comes from Greek 'thema' through Latin 'thema' into Modern English, and the formation '-themed' (as in 'space-themed', 'jungle-themed') is a modern compound pattern that attaches to nouns to mean 'having the theme of ...'.

Initially, 'frontier' meant 'border' or 'front' and 'theme' meant 'subject' or 'topic'; combined in modern usage to mean 'styled after or centered on the frontier', especially in entertainment, design, or descriptive contexts.