This is the 50th most frequent Lithuanian word.
kurios
"Kurios" in Lithuanian means "which" (feminine plural form).
In this sentence, 'kurios' serves as a relative pronoun referring to 'knygos' (books), which is feminine plural.
Čia yra knygos, kurios rekomenduoju perskaityti.
Here are the books which I recommend to read.
Here, 'kurias' is the feminine plural form in the accusative case, referring to 'nuotraukos' (photos).
Tai yra tos nuotraukos, apie kurias pasakojau vakar.
These are the photos about which I told you yesterday.
In this instance, 'kurios' functions as a relative pronoun in the genitive case, referring to 'mergaitė' (girl).