Is it ensure, insure, or assure?
branch of chemistry which deals with wine-making and brewing, 1868, from Greek zymo-, comb. form of zyme "a leaven" (from PIE root *yeue-; see juice) + -ourgia "a working," from ergon "work" (see urge (v.)).
The last word in many standard English dictionaries (and this one); but in the OED [2nd ed.] the last word is zyxt, an obsolete Kentish form of the second person singular of see (v.).