This is the 1125th most frequent Turkish word.
günün
"Of the day" or "the day's."
Here, 'günün' is the possessive form of the noun 'gün' (meaning 'day'), used to mean 'your day'.
Günün nasıl geçti?
How was your day?
Here, 'günün' shows possession, referring to 'the day's best time', indicating that the beautiful time belongs to the day.
Bugün günün en güzel saatindeyiz.
Today, we are in the best time of the day.
Here, 'günün' means 'of the day', functioning as a genitive case to indicate the relationship between 'gün' (day) and its meaning and significance.