This is the 87th most frequent Slovak word.
dní
The Slovak word "dní" means "days" in English (genitive plural form of "deň").
Here, 'dní' is the genitive plural form of 'deň' used to indicate a quantity or duration of time.
Máme voľno na sedem dní.
We have time off for seven days.
Here, 'dní' is used in a genitive construction to indicate possession or association of the mornings in the context of specific number of days.
Ráno dvanástich dní je obvykle slnečné.
The mornings of twelve days are usually sunny.
In this sentence, 'dní' is the genitive plural form, again showing quantification, combined with a descriptive adjective.