This is the 6700th most frequent Polish word.
dzieå
The Polish word "dzień" means "day" in English.
The word "dzień" is used to denote a specific day in the calendar.
Dziś jest piękny dzień.
Today is a beautiful day.
Here, "dnia" (genitive form of "dzień") is used to express the concept of 'on each day' in terms of time.
Każdego dnia uczę się czegoś nowego.
Every day, I learn something new.
"Dnia" (again genitive case) is employed in an expression indicating a portion of the day.