milk vs potable

milk and potable both are nouns.

Word	Noun	Adjective	Verb	Adverb
milk	Yes	No	Yes	No
potable	Yes	Yes	No	No

As nouns, potable is a hypernym of milk; that is, potable is a word with a broader meaning than milk:

milk: a white nutritious liquid secreted by mammals and used as food by human beings
potable: any liquid suitable for drinking

Other hypernyms of milk include dairy product, beverage, drink, drinkable.

milk (noun)	potable (noun)
produced by mammary glands of female mammals for feeding their young	any liquid suitable for drinking
a white nutritious liquid secreted by mammals and used as food by human beings
any of several nutritive milklike liquids

milk (adjective)	potable (adjective)
	suitable for drinking

milk (verb)	potable (verb)
take milk from female mammals
add milk to
exploit as much as possible