regional power; major regional nation
Refers to a country that holds significant influence, military strength, or economic weight within its own geographic region, without necessarily being a global superpower.
India is regarded as a regional power in South Asia.
That regional power is strengthening economic ties with neighboring countries.
超大国 means 'superpower', a nation with dominant global influence, while 地域大国 is limited to a specific region.
大国 is a general term for a 'major power' or 'great power', which can be global or regional; 地域大国 explicitly scopes the power to a region.
Compound of 地域 (region) and 大国 (great power, major nation). The term is a straightforward modern political concept.