adjective \ˈfat\

: having a lot of extra flesh on your body : having a lot of body fat

: having a full, rounded form

: unusually wide or thick


Full Definition of FAT

:  notable for having an unusual amount of fat:
a :  plump
b :  obese
c of a meat animal :  fattened for market
d of food :  oily, greasy
a :  well filled out :  thick, big <a fat book>
b :  full in tone and quality :  rich <a gorgeous fat bass voice — Irish Digest>
c :  well stocked <a fat larder>
d :  prosperous, wealthy <grew fat on the war — Time>
e :  being substantial and impressive <a fat bank account>
a :  richly rewarding or profitable <a fat part in a movie> <a fat contract>
b :  practically nonexistent <a fat chance>
:  productive, fertile <a fat year for crops>
:  being swollen <got a fat lip from the fight>
of a baseball pitch :  easy to hit
fat·ness noun

Examples of FAT

  1. The dog is getting fat because you feed him too much.
  2. I can't believe I've let myself get so fat.
  3. a fat book of poems
  4. a truck with fat tires

Origin of FAT

Middle English, from Old English ̄tt, past participle of ̄tan to cram; akin to Old High German feizit fat
First Known Use: before 12th century

Other Food Terms

Reuben, calamari, chuck, curry, edamame, foie gras, hummus, leaven, nonpareil, peel



Definition of FAT

transitive verb
:  to make fat :  fatten

First Known Use of FAT

before 12th century



: the soft flesh on the bodies of people and animals that helps keep the body warm and is used to store energy

: an oily solid or liquid substance in food

: an amount that is more than what is usual or needed

Full Definition of FAT

:  animal tissue consisting chiefly of cells distended with greasy or oily matter
a :  oily or greasy matter making up the bulk of adipose tissue and often abundant in seeds
b :  any of various compounds of carbon, hydrogen, and oxygen that are glycerides of fatty acids, are the chief constituents of plant and animal fat, are a major class of energy-rich food, and are soluble in organic solvents but not in water
c :  a solid or semisolid fat as distinguished from an oil
:  the best or richest part
:  obesity
:  something in excess :  superfluity <trim the fat from the news operation — Ray Olson>
fat·less \-ləs\ adjective

Examples of FAT

  1. people with excess body fat
  2. a diet and exercise program to help you gain muscle and lose fat
  3. Nuts contain a lot of fat.
  4. Trim the fat from the meat before you cook it.
  5. a diet low in fats
  6. fats like butter and olive oil
  7. trim the fat off the budget

First Known Use of FAT

14th century

Other Biochemistry Terms

bile, biodegradable, capsaicin, keratin, metabolism


noun    (Concise Encyclopedia)

Any organic compound of plant or animal origin that is not volatile, does not dissolve in water, and is oily or greasy. Chemically, fats are identical to animal and vegetable oils, consisting mainly of triglycerides (esters of glycerol with fatty acids). Fats that are liquid at room temperature are called oils. Differences in melting temperature and physical state depend on the saturation of the fatty acids and the length of their carbon chains. The glycerides may have only a few different component fatty acids or as many as 100 (in butterfat). Almost all natural fats and oils incorporate only fatty acids that are constructed from two-carbon units and thus contain only even numbers of carbon atoms. Natural fats such as corn oil have small amounts of compounds besides triglycerides, including phospholipids, plant steroids, tocopherols (vitamin E), vitamin A, waxes, carotenoids, and many others, including decomposition products of these constituents. Sources of fats in foods include ripe seeds and some fruits (e.g., corn, peanuts, olives, avocados) and animal products (e.g., meat, eggs, milk). Fats contain more than twice as much energy (calories) per unit of weight as proteins and carbohydrates. Digestion of fats in foods, often partial, is carried out by enzymes called lipases. The breakdown products are absorbed from the intestine into the blood, which carries microscopic fat droplets reconstituted from digested fats (or synthesized in cells) to sites of storage or use. Fats are readily broken down—primarily into glycerol and fatty acids—by hydrolysis, a first step for many of their numerous industrial uses. See also lipid.


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