This is the 782nd most frequent Ukrainian word.
дніпрі
"Дніпрі" is the locative case of "Дніпро," meaning "in/on the Dnipro" (a major river in Ukraine).
In this sentence, 'Дніпрі' is the locative case of 'Дніпро', which refers to the city Dnipro, indicating location.
Я живу в Дніпрі.
I live in Dnipro.
Here, 'Дніпрі' is used in the prepositional case of 'Дніпро', referring to the river Dnieper, indicating location with motion.
Кораблі пливуть по Дніпрі.
Ships are sailing on the Dnieper.
'Дніпрі' is used here in the prepositional case to talk about events happening on the river Dnieper.