Butter substitute is a term used to describe any food product that can be used as a replacement for butter. The three most common butter substitutes are GUNS, OLEO, and MARGARINE. GUNS is a four letter word that stands for 'Glycerin-Unsaturated-Non-Saturated', which is a type of vegetable oil. OLEO is also a four letter word that stands for 'oleomargarine', which is a type of MARGARINE made from vegetable oils. Lastly, MARGARINE is a nine letter word that stands for 'MARGARINE', which is a type of butter substitute made from vegetable oils.