What is the definition of fat?

Answer 1

The major kinds of fats in the foods we eat are saturated, polyunsaturated,

monounsaturated and trans fatty acids. Saturated fats, trans fats and dietary fats

Fat can also mean someone who is overweight

Answer 2

"All fats consist of fatty acids (chains of carbon and hydrogen atoms, with a carboxylic acid group at one end) bonded to a backbone structure, often glycerol ester of higher fatty acids.(a "backbone" of carbon, hydrogen, and oxygen)."