I find it mildly irritating when people misuse the word "tea". Tea - in it's true form - is the the tea tree (Camellia sinensis), or any preparation thereof. The most common method of preparing this plant is to make an infusion by steeping the leaves in hot water.
The leaves are, after harvesting, carefully processed by oxidation, steaming, rolling, roasting, or aging to produce white tea (nearly no oxidation), green tea (slight oxidation), oolong teas (a wide range here, but this includes anything more heavily oxidized than green tea, and less than black tea), black tea (fully oxidized, though often called "red tea" in China), and pu-erh which has been aged and is sometimes bacterially fermented (the Chinese call some types of pu-erh "black tea" - this is a source of some confusion. You can get by with the term "Hei Cha"). Tea leaves, infusions, tinctures, etc, are sometimes used in cooking and alternative medicine.
(please note that I am more familiar with Chinese tea than Japanese, Indian, or Other tea. I will leave Matcha and Hojicha alone)
Sometimes tea can be flavored or scented. There's Earl Grey which is black tea mixed with Lavender and Saffron. There is Jasmine tea, typically made of a low-grade Chinese or Japanese green tea which has been scented with Jasmine flowers. I have encountered an endless variety of scented teas, and mixes which can barely be called "tea". Here a problem arises.
The word "tea" is often used when one speaks of things that are contain no C. sinensis. Of course we have "chamomile tea", "mint tea", "stinging nettle tea", et cetera. Gardeners may even be familiar with the "compost tea" or "manure tea" - infusions made from holding compost or manure in water which then absorbs vital nutrients for plants.
These preparations of organic matter are sometimes called "herbal teas". This nomenclature alludes to the fact that such liquids are not made from the tea tree. There is still a problem, though - the word "tea" is still where it should not be. The proper terms for such preparations are: Infusion, and Tisane
This is just one small example of the misuse of words which runs rampant in our language. Other examples include:
The word "temper" used in order to mean any range of metallurgical operations (tempering is the reheating of high carbon steel after it has been hardened in order to reduce brittleness. Many use "tempering" to mean hardening or even carburization).
The word "like". This is possibly the most widely-abused word in the English language. The word "like" is used mainly as a filler word today. It's impossible to escape from such flim-flam these days. Even I find an unwelcome "like" escaping from my mouth from time to time.
The currency of expression in the English language is being debased!
This senseless must come to an end!
Like, totally! 