A monosaccharide is a type of simple sugar, which is composed of one molecule and is the most basic form of carbohydrates. The three common monosaccharides are OSE (3 letters), GLUCOSE (7 letters), HEXOSE (6 letters) and FRUCTOSE (8 letters). OSE is an abbreviation for oxosoacetate, which is a type of monosaccharide that is found in plants. GLUCOSE is the most abundant monosaccharide and is the primary source of energy for living organisms. Hexose is another type of monosaccharide that is found in plants and animals. Fructose is a monosaccharide that is found in fruits and honey and is sweeter than GLUCOSE.