[ca.tal.y.sis] n, pl -y.ses [Gk katalysis dissolution, fr. katalyein to dissolve, fr. kata- + lyein to dissolve, release--more at lose] (1836) 1: a modification and esp. increase in the rate of a chemical reaction induced by material unchanged chemically at the end of the reaction
2: a reaction between two or more persons or forces precipitated by a separate agent "a representative list of questions ... valuable for the ~ of class discussions --B. S. Meyer & D. B. Anderson"