Most lipids are esthers of alcohol (glyeceral) and fatty acids. Glyceral has hydroxylic group (oit), all of which form an esther. Usually, when all 3 hydroxyl group undergo condensation reaction the lipid formed is called a Triglyceride. Each of the all group of glycerol molecule reacts with the carboxylic group of fatty acid to form water. This is a condensation reaction leading to removal of S water molecules and formation of esther bonds bins the glycerol and the fatty acid. If reaction is reverse, the lipid will be hydrolised into fatty acid and glycerol.

A Triglyceride can be simple or complex, his salt to be simple if there is only one kind of fatty acid present and complex when there are different kinds of fatty acid.