This is the 1658th most frequent Russian word.
натальи
"Натальи" is the genitive or plural form of the name "Наталья" (Natalia), meaning "of Natalia" or "Natalias".
The word 'Наталье' is used in the dative case to indicate possession or relation.
Эта книга принадлежит Наталье.
This book belongs to Natalya.
The word 'Наталью' is in the accusative case, as it is the direct object of the verb 'встретил'.
Я встретил Наталью вчера в магазине.
I met Natalya yesterday at the store.
The word 'Натальей' is in the instrumental case, used here because of the preposition 'с' to indicate accompaniment.