This is the 66th most frequent Ukrainian word.
країни
"Countries."
The word 'країни' here is in the genitive plural case of the noun 'країна', and it is used to indicate plurality in the context of referring to several countries.
Ми плануємо подорожувати до різних країн Європи.
We plan to travel to different countries in Europe.
'Країн' is in the genitive plural case, used after the preposition 'з', indicating origin or association with multiple separate countries.
Сім'я з різних країн зібралася разом на свято.
Families from different countries gathered together for the celebration.
Here, 'країни' is in the genitive singular form, indicating possession to show that the success belongs to the country.