This is the 411th most frequent Polish word.
stolicy
"Stolicy" means "of the capital" (genitive form of "stolica").
The word 'stolicy' is used here in the localization context, indicating 'in the capital' as the locative case form of 'stolica' (capital).
Warszawa jest stolicą Polski, a w stolicy mieszka wielu ludzi.
Warsaw is the capital of Poland, and many people live in the capital city.
The word 'stolicy' again demonstrates its locative case usage where it specifies the location being referred to, that is, the capital city.
W stolicy znajdują się ważne instytucje rządowe.
There are important government institutions in the capital.
The word 'stolicy' here continues to reflect its application in providing a locative context, showing the place where an activity (visiting) is planned.