This is the 775th most frequent Lithuanian word.
koncertų
The Lithuanian word "koncertų" means "concerts" (genitive plural form).
The word 'koncertų' is used as a possessive form, indicating ownership of the halls by concerts, hence 'concert halls'.
Vakar lankiausi dviejuose koncertų salėse.
Yesterday, I visited two concert halls.
Here 'koncertų' specifies tickets associated with concerts, implying tickets that are from various concerts.
Man patinka rinkti koncertų bilietus.
I like to collect concert tickets.
In this case, 'koncertų' describes the program as being related to concerts, showing a genitive case relationship to its context.