lact- combining form orlacti-orlacto- Etymology:lact- from F&Latin; French, from Latin, from lact-, lac; lacti- from French & Late Latin; French, from Late Latin, from Latin lact-, lac; lacto- from lact- + o- — more at galaxy 1.milk < lactalbumin > < lactometer > < lactigenic > 2. a.: lactate and < lactophosphate > b.: lactic acid < lactamide > < lactonitrite > c.: lactose < lactitol > < lactobionic acid >