This is the 7715th most frequent Russian word.
зеленого
"Зеленого" means "of green" or "green" in the genitive or accusative case in Russian.
In this sentence, "зеленого" is used as an adjective in the genitive singular form to describe the noun "яблока," indicating the color green.
Я купил килограмм зеленого яблока.
I bought a kilogram of green apples.
Here, "зеленого" is a genitive singular form used to describe the noun "цвета," referring to the color green.
Моя машина имеет оттенок зеленого цвета.
My car has a shade of green color.
In this case, "зеленого" is used substantively in the genitive singular to refer to greenery or the concept of the color green in general.