What is "lactis" or "lactic"?

Answer #1

Definition of LACTIC(from the Merriam-Webster online dictionary)

1 a : of or relating to milk b : obtained from sour milk or whey

2: involving the production of lactic acid

Answer #2

A word referring to milk, milk production, or mere appearance of milk. Lactic acid (the reason why we have sore muscles after exercise) is white and milky. Galactose is the carbohydrate found in milk. etc. etc.