This is the 281st most frequent Chinese word.
国
"Country" or "nation."
"国" means "the entire country" here, emphasizing national-scale events.
全国人民都在庆祝这个节日。
The people of the whole nation are celebrating this festival.
"国" is used to denote a specific country being represented.
参赛者代表自己的国家参加比赛。
Participants represent their own countries in the competition.
"国" refers to a country or nation in this context.