• 母国ぼこく — mother country / homeland
• 愛国あいこく — patriotism
• 帰国きこく — return to one’s country
• 天国てんごく — heaven / paradise
• 外国がいこく — foreign country
• 中国ちゅうごく — China
• 国語こくご — national language / Japanese
• 国会こっかい — National Diet / Parliament
• 国立こくりつ — national (institution)

国 uses the radical 囗 (enclosure) with 玉 (treasure), originally referring to a protected territory. Over time, it came to mean a country, nation, or state.