In this simplified form, this character consists of 玉, the Chinese character for jade (or precious stone or gem) (representing the emperor), enclosed by the character meaning "erect," "proud," or "upright". In the Kangxi Dictionary of 1716 the character 国 is not included, but other characters like 囯, 囶, 圀 and 䆐 are. 國 is the original character.
The on'yomi is used in compounds like 国語 (こくご, Kokugo: "national language", i.e. Japanese) or 中国 (ちゅうごく, Chūgoku: China; the Chūgoku region of central Japan). In many compounds where the 国 character does not come first, koku changes to goku due to rendaku (連濁).