The noun 国王 (guówáng) means "king" and refers to a male monarch or sovereign ruler of a country. It is often used in contexts involving royalty, history, or politics. For example, 未来的国王 means "the future king."
那位国王统治了这个国家四十年。
nà wèi guówáng tǒngzhì le zhège guójiā sìshí nián.
That king ruled this country for forty years.
历史上这个国王非常受人民爱戴。
lìshǐ shàng zhège guówáng fēicháng shòu rénmín àidài.
In history, this king was greatly loved by the people.
国王住在山上的城堡里。
guówáng zhù zài shān shàng de chéngbǎo lǐ.
The king lives in a castle on the mountain.