LACTOYL Meaning of LACTOYL in English ˈlaktəˌwil nounor lac·tyl ˈlakˌtil( -s )Etymology: International Scientific Vocabulary lact- + -oyl or -yl : the radical CH 3 CH(OH)CO− of lactic acid Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012