metabolite content trait lipid content trait fat content (narrrow) Lipids are triglycerides, esters of three fatty acid units joined to glycerol, a trihydroxy alcohol. A triglyceride is called a fat if it is a solid at 25°C; it is called an oil if it is a liquid at that temperature. Fats have a predominance of saturated fatty acids, and oils are composed largely of unsaturated acids. TO:0000604 fat and oil content (exact) plant_trait_ontology oil content (narrow) A metabolite content trait (TO:0000281) which is the amount of lipid in a plant structure (PO:0009011).