[bahy-uh-seet-l, -set-l, bahy-as-i-tl]
noun Chemistry.
  1. a yellow, water-soluble liquid, C4H6O2, 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.

Origin of biacetyl Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018