This is the 213th most frequent Czech word.
milionu
"Milionu" is the genitive or dative singular form of "milion," meaning "of a million" or "to a million."
Here, 'milionů' is used in the genitive plural to indicate the quantity of currency in crowns.
Vyhrál loterii a dostal pět milionů korun.
He won the lottery and received five million crowns.
'Milionů' in this sentence again is in the genitive plural, referring to an approximate number of millions.
Počet obyvatel činí několik milionů.
The population numbers several millions.
In this sentence, 'milionů' represents the genitive plural form of 'milion' in the context of quantifying people.