a. Containing fat, or having the qualities of fat; greasy; gross; as, a fatty substance. [ 1913 Webster ]

Fatty acid (Chem.), any one of the paraffin series of monocarbonic acids, as formic acid, acetic, etc.; -- so called because the higher members, as stearic and palmitic acids, occur in the natural fats, and are themselves fatlike substances. --
Fatty clays. See under Clay. --
Fatty degeneration (Med.), a diseased condition, in which the oil globules, naturally present in certain organs, are so multiplied as gradually to destroy and replace the efficient parts of these organs. --
Fatty heart,
Fatty liver, etc. (Med.), a heart, liver, etc., which have been the subjects of fatty degeneration or infiltration. --
Fatty infiltration (Med.), a condition in which there is an excessive accumulation of fat in an organ, without destruction of any essential parts of the latter. --
Fatty tumor (Med.), a tumor consisting of fatty or adipose tissue; lipoma. [ 1913 Webster ]