'chiasmus' originates from Greek, specifically the word 'χιασμός' (khiasmos), where 'chi-' referred to the Greek letter 'chi' (χ) meaning 'X' and the verb 'chiázō' (χιάζω) meant 'to cross or mark with an X'.

'chiasmus' changed from the Greek word 'χιασμός' into Late Latin and Medieval Latin as 'chiasmus', and the term entered modern English usage via scholarly and rhetorical Latin and Greek studies.

Initially, it referred to an X-shaped crossing or mark; over time it evolved to denote both the physical crossing (in biology) and the rhetorical pattern of reversal (the current primary sense in literary and linguistic contexts).