lactalbuminEnglishOxford New American Dictionarylactalbumin /ˌlaktalˈbyo͞omən, ˌlæktælˈbjumən / ▸ noun Biochemistry a protein or mixture of similar proteins occurring in milk, obtained after the removal of casein and soluble in a salt solution. – ORIGIN late 19th century : from lacto- ‘of milk’ + albumin.