Tea's entomology originates in Chinese which has a vast history of pretty vague terms. This could be blamed on the chinese written0 language being comprised of pictograms, ideograms, phono-semantic compounds and others. however whatever the cast is chinese has a slight etomological habit of grouping somethings that may have an english learners scratch their head. examples that comes to mind is there use of their word alcohol 酒jiǔ this the way you label almost all liquors, wines, beer, etc.. is almost always something酒. using the word liquor instead of 酒 here are some examples. Do you want a red wine? you want red liquor. Want some sake? Ask for clear liquor. want beer? you may have to specify beer liquor. there are exemptions to this but you can see how even though all of those examples have very different being made they still are put under the same label of being just alcohol. When it come to tea the word came from 荼tú which then changed to 茶chá. tú even at the time were a vague group of bitter vegetables and was originally used as kind as a soup. So while modern tea may wish they had developed some more exact terms the colloquial use of it lends a lot of it to chinese/indian languages.