/buy'euh seet"l, -set"l, buy as"i tl/ , n. Chem.
a yellow, water-soluble liquid, C 4 H 6 O 2 , occurring in butter and in certain essential oils, as bay, and also synthesized: used chiefly to augment the flavor and odor of vinegar, coffee, and other foods.
Also, diacetyl .
[ BI- 1 + ACETYL ]