1A country or nation-state — a politically organized territory with its own government and people.
日本は島国です。
Japan is an island country.
世界には190以上の国があります。
There are more than 190 countries in the world.
彼女はいろんな国を旅行したことがある。
She has traveled to many different countries.
その国は経済成長が著しい。
That country's economic growth is remarkable.
2A region or area, often used as part of place names such as 西国 (the western provinces) or 北国 (the snowy north).
北国では冬になると雪が多く降る。
In the snowy north, a lot of snow falls in winter.
彼は西国の出身で、方言が少し違う。
He's from the western provinces, so his dialect is a bit different.
3The national or central government, used as the subject in expressions like 'the government does such-and-such.'
国は新しい支援制度を始めた。
The government started a new support program.
この道路は国の予算で作られた。
This road was built with national government funds.
国の方針に従って、学校の制度が変わった。
The school system changed in accordance with government policy.
4One's home country or hometown — the place one considers home.
卒業したら国に帰るつもりです。
I plan to go back home after graduating.
国の家族とはよく電話で話します。
I often talk on the phone with my family back home.
彼は10年前に国を離れて、日本に来た。
He left his home country ten years ago and came to Japan.
5A historical administrative province of Japan under the ritsuryō system, as in old province names like 出雲国 (Izumo).
昔の日本は多くの国に分かれていた。
Old Japan was divided into many provinces.
出雲国は現在の島根県にあたる。
Izumo Province corresponds to present-day Shimane Prefecture.
6A literary or classical usage meaning land or earth; rarely used in modern Japanese.
万葉集には「国」を大地の意味で使った歌がある。
The Man'yōshū contains poems that use 'kuni' to mean the land itself.