四

The Chinese character 四 (sì) for "four" is composed of two parts: the upper part is the character 三 (sān) for "three", and the lower part is a horizontal line. The character 四 originally meant "four" in ancient Chinese, and it was also used to represent the fourth day of the lunar month. In modern Chinese, the character 四 is still used to represent the number four, and it is also used in many other words and phrases, such as 四季 (sìjì) for "four seasons", 四海 (sìhǎi) for "the four seas", and 四书 (sìshū) for "the Four Books".The character 四 is also used in many Chinese idioms and proverbs, such as 四海之内皆兄弟 (sìhǎi zhī nèi jiē xiōngdì) for "all people within the four seas are brothers", and 一年之计在于春 (yī nián zhī jì zài yú chūn) for "the plan for a year lies in spring". These idioms and proverbs reflect the rich cultural and historical heritage of the Chinese language.