This is the 41st most frequent Japanese word.
県
Prefecture.
The word '県' is used to refer to individual prefectures in Japan while discussing their unique features.
学校では各県の特徴について学びます。
At school, we learn about the characteristics of each prefecture.
Here, '県' refers to a specific administrative region in Japan, Aomori Prefecture.
私の弟は青森県に住んでいます。
My younger brother lives in Aomori Prefecture.
In this sentence, '県内' means 'within the prefecture,' using '県' to denote a general administrative unit.