The crossword solutions for the term 'butter substitute, in short' are MARGE (5 letters), OLEO (4 letters), and GUNS (4 letters). MARGE is an acronym for Margarine, a butter substitute made from vegetable oils. Oleo is another name for margarine, derived from the Latin word oleum, meaning oil. GUNS is an acronym for 'Greater Use of Non-hydrogenated Substitutes', a campaign to encourage people to use margarine instead of butter.