This is the 7856th most frequent Russian word.
калькутта
"Калькутта" is the Russian name for "Kolkata," a city in India.
Here, 'Калькутта' is a proper noun referring to the geographical place, Kolkata.
Калькутта — это крупный город в Индии.
Kolkata is a major city in India.
In this sentence, 'Калькутты' indicates location, showing the genitive case form of the noun for 'Калькутта'.
Вчера мне приснился сон, в котором я гулял по улицам Калькутты.
Yesterday, I dreamed I was walking through the streets of Kolkata.
Here, 'Калькутте' represents the prepositional case when discussing something happening in Kolkata.