national history; Japanese history
Refers to the history of a nation, especially Japan. In Japanese contexts, it often specifically means Japanese history as an academic subject or field of study.
彼は大学で国史を専攻している。
He is majoring in Japanese history at university.
国史
We learned about the Kamakura period in Japanese history class.
world history
Chinese history
Compound of 国 (country, nation) and 史 (history). The reading こくし is the on'yomi of both characters.