'realism-based' originates from English by combining the noun 'realism' and the adjective-forming past-participle 'based', where 'realism' referred to the practice or theory of representing things as they are and 'based' indicated 'having a base or foundation'.

'realism' entered English from French 'réalisme' in the 19th century, ultimately from Latin 'realis' ('real') and Latin 'res' meaning 'thing'. 'base' comes from Old French 'base', from Late Latin/Greek 'basis' meaning 'step' or 'foundation'. These elements combined in English to form compounds like 'X-based' (e.g. 'evidence-based'), producing 'realism-based'.

Initially, 'realism' described the idea or movement concerned with depicting reality and 'based' simply meant 'having a base'; over time the compound 'realism-based' came to mean specifically 'grounded in realistic principles or methods'.