This is the 10765th most frequent Polish word.
dwudziestolecia
"Dwudziestolecia" translates to "of the twenty-year period" or "of the two decades."
Here, 'dwudziestolecia' refers to the twenty-year period between World War I and World War II, known as the interwar period.
Ruch artystyczny dwudziestolecia międzywojennego w Polsce był pełen innowacji.
The artistic movement of the interwar period in Poland was full of innovation.
In this sentence, 'dwudziestolecia' refers to a specific twenty-year span of the speaker's life.
Wspomnienia z mojego dwudziestolecia życia są pełne radości i beztroski.
Memories from my twenty years of life are full of joy and carefreeness.
This usage of 'dwudziestolecia' indicates the twentieth anniversary or a twenty-year existence period of an institution.