Japanese and Milk

The Japanese word for “milk” is “miiruku,” which is a Japanization of the English word “milk.”

But, Japanese mothers have been nursing their babies for as long as there have been people on those islands, else there would be no more Japanese. Surely they had a word to describe what came out of a mother’s breast before traders and missionaries started speaking English to them.

What is/was the Japanese word for the stuff that comes out of a mother’s breast? Do they still use it (the word), like in the context of science and medicine and whatnot?

From what I understand, they have a ton of different words for milk. Cow’s milk is one word, breast milk is a different word, the powder you put in your coffee is another word, etc.

Isn’t miruku just related to the coffee version of milk, for example, and cow’s milk is gyuunyuu (pardon the spelling), for example?

Miruku is not used as a general word for milk; it is almost always used as another word for gyunyu, cow milk. The latter word is still used often, perhaps with roughly equal frequency. I would be surprised to see the word miruku used in a newspaper or academic context.

Bonyu is the word for mother’s milk.