This is the 7573rd most frequent Polish word.
kwiecień
April.
In this sentence, 'kwiecień' is used as a noun to refer to the month of April.
Kwiecień jest moim ulubionym miesiącem w roku.
April is my favorite month of the year.
Here, 'kwietniu' is the locative form of the noun 'kwiecień', used to indicate time or location within that month.
W kwietniu zaczyna się wiosna.
Spring begins in April.
In this phrase, 'kwiecień' is used poetically as the subject of a saying, reflecting the unpredictable nature of the month of April.