triglyceride, ester formed from glycerol and one to three fatty acids. Fats and oils are triglycerides. In a simple triglyceride such as palmitin or stearin, all three fatty-acid groups are identical. In a mixed triglyceride, two or even three different fatty-acid groups are present; most fats and oils contain mixed triglycerides.

Any of an important class of naturally occurring lipids, esters in which three molecules of fatty acids are linked to glycerol. The three fatty acids may be all the same kind or different kinds. The types of triglycerides in animals vary with the species and the fats in their food. In mammals they are stored in adipose tissue until needed and then broken down to the glycerol and fatty acids. Many vegetable triglycerides (oils) are liquid at room temperature, unlike those of animals, and tend to contain a greater variety of fatty acids. In alkali, triglycerides break down to form glycerol and three molecules of soap (saponification).

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