'peptidyl' originates from the modern chemical formation combining 'peptide' + the suffix '-yl', where 'peptide' ultimately derives from Greek roots related to 'pepsis/peptein' meaning 'to digest' and the suffix '-yl' denotes a radical or substituent group in chemical nomenclature.

'peptidyl' was formed in modern scientific English by attaching the 19th-century chemical suffix '-yl' (from French/Neo-Latin usage) to 'peptide' (a term adopted into European languages in the late 19th / early 20th century from Greek-derived forms), producing the current technical term 'peptidyl'.

Initially the Greek root for 'peptide' related to 'digested' or 'cooked', but over time 'peptide' came to mean 'a short chain of amino acids'; combined with '-yl', the modern term 'peptidyl' now specifically denotes something relating to or constituting a peptide group.