'athbash' originates from Hebrew, specifically the acrostic name formed from the letters 'Aleph' and 'Tav' and 'Bet' and 'Shin' (often written as 'אַתְבָּשׁ' or transliterated 'atbash'), where the sequence of letters names the pairing used in the substitution (first with last, second with second-last).

'athbash' changed from the Hebrew acrostic 'אַתְבָּשׁ' (transliterated 'atbash') used in Jewish exegetical and cryptographic contexts; the term entered scholarly discussion in Medieval and later writings about Biblical cryptography and was adopted into modern English as 'Atbash' or variants like 'athbash'.

Initially, it meant the specific Hebrew letter-reversal cipher used in Biblical and rabbinic texts; over time it broadened to mean any reverse-alphabet substitution cipher (applied to other alphabets as well).