LACT- Meaning of LACT- in English [lact-] or lacti- or lacto- comb form [F & L; F, fr. L, fr. lact-, lac--more at galaxy] 1: milk "lactoglobulin" 2. a: lactic acid "lactate" b: lactose "lactase" Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012