1) The formation of glucose from noncarbohydrate precursors, such as pyruvate, amino acids and glycerol.

2) Formation of glucose within the animal body from precursors other than carbohydrates especially by the liver and kidney using amino acids from proteins, glycerol from fats, or lactate produced by muscle during anaerobic glycolysis -- called also glyconeogenesis.

3) The process of making glucose (sugar) from its own breakdown products or from the breakdown products of lipids (fats) or proteins. Gluconeogenesis occurs mainly in cells of the liver or kidney.