Second, both are not milks. Milks are what comes out of animals mammary glands (even legally in most jurisdictions). Advertisers and "health product" peddlers h

Second, both are not milks. Milks are what comes out of animals mammary glands (even legally in most jurisdictions). Advertisers and "health product" peddlers hijacked the term (that existed for millennia) to mean "random juices". The word milk has a somewhat broader meaning than what comes out of mammary glands. I would say that the default meaning, with no other modifier, is definitely mammary gland output. But checking various dictionaries I see definitions that include: The white juice of certain plants, such as coconut milk. A food product produced from seeds or fruit that resembles and is used similarly to cow's milk, such as coconut or soy milk. A liquid resembling milk in appearance such as the latex of a plant. And there's milk of magnesia. I don't know when these various terms came into use, but the Online Etymology Dictionary suggests milk of almond and similar constructions have been around since the late 14th century: https://www.etymonline.com/word/milk%20of%20magnesia https://www.etymonline.com/word/milk%20of%20magnesia