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home country; one's own country; country of origin
suzerain country (from the perspective of the vassal state); colonizing country
country of one's ancestors
this country
留学生たちは卒業後に本国へ戻る予定だ。
The international students plan to return to their home countries after graduation.
大使は任期を終えて本国に帰国することになった。
I returned to my home country.
外交官は重要な決定について本国の指示を仰いだ。
I sought instructions from the home country.