fatty acid
noun
°Any of a class of aliphatic carboxylic acids, of general formula CnH2n+1COOH, that occur combined with glycerol as animal or vegetable oils and fats. Only those with an even number of carbon atoms are normally found in natural fats.
"Note: The above general formula applies to the saturated fatty acids. Remove 2 hydrogen atoms for an unsaturated fatty acid, and 2 hydrogen atoms for every double bond in a polyunsaturated fatty acid."