English English Wikipedia has an article on:diacetylWikipedia Etymology From di- + acetyl. Noun diacetyl (uncountable) (organic chemistry, in combination) Two acetyl groups in a compound (organic chemistry) Synonym of butanedione Derived terms dacisteinediacetylmorphinediacetylnalorphinediacetylurea See also (butanedione): popcorn lung (a condition caused by inhaling diacetyl) artificial butter flavor (the flavoring derived from diacetyl)Wikiwand - on Seamless Wikipedia browsing. On steroids.