cat·e·chin \ˈkad.əchə̇n, -əsh-, -ək-\noun (-s) Etymology: German katechin, from katechu catechu (from English) + -in — more at catechu 1.: a white crystalline phenol-alcohol C15H14O6 related chemically to the flavones and found as the dextrorotatory form in catechu — called also catechol 2.: pyrocatechol