the cardinal number twenty-three.

thirteenth day of a month

the Thirteen Confucian Classics, namely: Book of Songs, Book of History, Rites of Zhou, Rites and Ceremonies, Classic of Rites, Book of Changes, Mr Zuo's Annals, Mr Gongyang's Annals, Mr Guliang's Annals, The Analects, Erya, Classic of Filial Piety, and Mencius

half-witted, silly, or behaving in an eccentric and foolish manner

thirteen peaks of Meili Snow Mountains in Diqing Tibetan Autonomous Prefecture, Yunnan

the Ming tombs (mausoleum park of the Ming emperors in Changping district of Beijing)