What is "diacetyl"

n. 1 (context organic chemistry in combination English) Two acetyl groups in a compound 2 (context organic compound English) butanedione

Diacetyl ( IUPAC systematic name: butanedione or butane-2,3-dione) is an organic compound with the chemical formula (CHCO). It is a yellow/green liquid with an intensely buttery flavor. It is a vicinal diketone (two C=O groups, side-by-side) with the molecular formula CHO. Diacetyl occurs naturally in alcoholic beverages and is added to some foods to impart its buttery flavor.