I am, as I think I’ve mentioned here before, a recovering stickler: while I intellectually support the growth and change of English as she is spoken (and written and texted) I am still instinctively appalled by anything that I was ever taught was wrong. Even if, as is so often the case, the ‘wrong’ usage is not wrong at all, and has been in perfectly reasonable use for hundreds of years.
One such that came to mind recently (In the novella A Psalm for the Wild-Built by Becky Chambers, among others) is the use of tea to describe any hot-water-and-plant-matter beverage. As far as I am concerned, tea is made from the leaves of the Camellia plant. Oh, perhaps there might be a little bergamot oil or vanilla involved in the fermentation process, and I suppose it might even be flavored with a tiny bit of citrus or jasmine, but proper tea is made primarily from, well, tea.
Why do Marxists drink herbal tea? Because proper tea is theft!
Ahem. I do apologize.
At any rate, in point of fact the word tea has been used for lots of kinds of infusions for hundreds of years. The great weight of custom is behind it. In fact, Isaac Watts, in Logic: Or The Right Use of Reason in the Inquiry After Truth, uses the word tea as an example of a word whose use has gone from the specific to the general:
Note […] that a proper name may become in some sense common, when it hath been given to several beings of the same kind; so Cæsar, which was the proper name of the first emperor Julius, became also a common name to all the following emperors. And tea, which was the proper name of one sort of Indian leaf, is now-a-days become a common name for many infusions of herbs, or plants, in water; as sage-tea, ale-hoof-tea, limon-tea, &c.
So it was too late for my cranky sticklerish insistence on a narrow use of the word tea by 1725, at the latest.
Continuing the theme of my wrongness, I have generally been using the word tisane for hot-water infusions that are not based on the Camellia leaf. Looking up the usage of that word, I discovered that a tisane is properly speaking only made from barley, except of course that’s not how the word is commonly used either.