This is the 755th most frequent Russian word.
театра
The word "театра" is the genitive or prepositional singular form of "театр," meaning "theater."
This usage of 'театра' is in the genitive case, indicating the source or origin.
Я иду из театра.
I am coming from the theater.
Here, 'театра' is also in the genitive case to express possession or limitation.
Билеты в театра больше нет.
There are no more tickets for the theater.
In this sentence, 'театра' is again in the genitive case, used after a preposition to indicate location or proximity.