China — the country (People's Republic of China), one of the world's most populous nations.
中国は世界で最も人口の多い国の一つだ。
China is one of the most populous countries in the world.
来月、中国へ出張に行く予定です。
I'm scheduled to go on a business trip to China next month.
中華料理は中国各地で大きく異なる。
Chinese cuisine varies greatly across different parts of China.
The Chūgoku region — the western part of Honshu in Japan (prefectures such as Okayama, Hiroshima, Yamaguchi, Tottori, Shimane).
広島は中国地方に位置している。
Hiroshima is located in the Chūgoku region.
出張で中国地方を数日間まわった。
I toured the Chūgoku region for several days on a business trip.
The central part of a country; the main or central region of a state (used in a general/older sense).
歴史的にその都市は国の中国にあたり、交通の要所となった。
Historically, that city corresponded to the country's 'central region' and became an important transport hub.
A historical term (read as ちゅうこく) used under the ritsuryō system to denote a province of the second-lowest rank.
律令制の史料には『中国（ちゅうこく）』という表現が見られる。
Historical ritsuryō documents contain the expression 'chūkoku' (中国).