"substance which speeds a chemical reaction but itself remains unchanged," 1900, formed in English (on analogy of analyst) from catalysis. Figurative use by 1943.
1836, from French margarine, a chemical term given to a fatty substance obtained from animal and vegetable oil, coined by French chemist Michel Eugène Chevreul (1786-1889) in 1813 from (acide) margarique "margaric (acid);" literally "pearly," from Greek margaritēs "pearl" (see Margaret). So called for the luster of the crystals. Now discarded in this sense as a chemical term, but preserved in margarine.