'dealkylation' originates from the combining form of 'de-' (from Latin 'de-' meaning 'removal' or 'from'), the chemical radical name 'alkyl' (coined in organic chemistry from 'alcohol' + the suffix '-yl' used for radicals), and the noun-forming suffix '-ation' (from Latin '-ationem').

'alkyl' was coined in 19th-century chemical nomenclature (from words like 'alcohol' plus the suffix '-yl'); combined with the prefix 'de-' and '-ation', the term evolved in scientific English to 'dealkylation' to denote removal of an alkyl group.

Initially the components referred simply to 'removal' ('de-') and the 'alkyl' radical; over time the combined term came to be used as a specific technical noun meaning 'the process of removing an alkyl group'.