This is the 18211th most frequent Russian word.
черешни
Sweet cherries.
In this sentence, 'черешни' refers to cherry fruit trees, used in plural form to describe where they grow.
В саду растут черешни.
Cherry trees grow in the garden.
Here, 'черешни' refers to the cherry fruits themselves, and it is used in the singular genitive form ('черешни') because it is the object of the measure phrase ('килограмм').
Я купил килограмм черешни на рынке.
I bought a kilogram of cherries at the market.
In this instance, 'черешни' refers to the cherry fruits, used in plural form as the subject to describe their taste.