This is the 5191st most frequent Japanese word.
長期間
"Long period of time."
Used as a time duration qualifier meaning 'long period of time'.
長期間この問題について考えてきました。
I have been thinking about this problem for a long period.
Used to describe the duration of an event, meaning 'extended time frame'.
この地域は長期間の乾季があります。
This region experiences a long dry season.
Used to indicate a long-term usage or state.