Yes, or "пластиковый стаканчик", which also happens to be a plastic cup in English. And here is where some of the confusion may be. Another example where English and Russian do not align in terms may be this:
This is clearly a wine glass in English but in Russian we will never use the word "стакан" to describe this object. It would be called "бокал" or sometimes "фужер" in its fancier version.
Going back to the original question in this thread, I just want to clarify one moment. The distinction between various drinking vessels in Russian is about the form and size. The material rarely matters.
For example, "стакан" would be something cylindrical or slightly conical, without a handle, with the hight normally being bigger than the diameter. The volume would be between 200 and 300 ml.
"Чашка", on the other hand, is usually hemispherical (this is what the root "чаш" means) or some modification of hemispherical, with a handle (for tea or coffee) or even with two (for consommé). The volume ranges between 50 and 300 ml, depending on the purpose.
A glass of tea in America usually means iced tea sweetened (with sugar) in the south or unsweetened everywhere else. In the south waitresses will ask because they are brewed in separate containers. a cup of tea is hot tea. My understanding, from watching movies, in Russia a glass of tea is a clear glass sitting in a metal holder and is hot from a samovar.
I definitely saw metal holders and held such holders in the trains. And yeah, I drank tea from a samovar... 25 years ago?
These are mostly things of the past. I do still drink tea from a faux Soviet-style glass at work but, sadly, smashed my genuine glass at home. Now I use a mug just like most people, I guess.
RIP the glass.
How would you say: This is HER glass of juice? So when the possessor of the glass is a female. Namely, why do you translate HIS glass, you could translate here also HER glass because as far as I understand the possessive adjective is concorded with стакан that is masculine. I could not use её стакан.
In English nouns do not have gender so you use HIS or HER to indicate the gender of the possessor but in Russian ...
стака́н (stakán) [stɐˈkan] m inan (genitive стака́на, nominative plural стака́ны, genitive plural стака́нов) "drinking glass" From Old East Slavic достаканъ (dostakanŭ), from Turkic (compare Chagatai tostakan (“wooden bowl”), Tatar тустыган (tustığan, “cup”), Bashkir туҫтаҡ (tuθtaq, “cup for drinking koumiss”), Kazakh тостаған (tostağan, “wooden cup”)).