noun
the whole nation; all the people of the country
Refers to the entire population of a country collectively, often used in political or statistical contexts.
全国民がそのニュースに注目した。
The whole nation paid attention to the news.
この政策は全国民に影響を与える。
This policy affects all the people of the country.
全国 means 'the whole country' as a geographical or administrative area, whereas 全国民 specifically refers to the people living there.
Compound of 全 (ぜん, 'all') + 国民 (こくみん, 'people of the nation').