Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Acronyms, Wikipedia. Li,symbol for the element lithiumlithium [Gr.,=stone], metallic chemical element; symbol Li; at. no. 3; interval in which at. wt. ranges 6.938–6.997; m.p. about 180.54°C;; b.p. about 1,342°C;; sp. gr. .534 at 20°C;; valence +1. Lithium is a soft, silver-white metal. ..... Click the link for more information. .(self-designation, Lai), the common Chinese name for the Tai-speaking aborigines of the island of Hainan (People’s Republic of China). Population, about 500,000 (1967 estimate). The Li language belongs to the Tai family of languages. Animistic beliefs and the ancestor cult are widespread among the Li. The center of their settlement is the Wuchi Shan, where an autonomous district for the Li and Miao peoples was created in 1952. The principal occupations of the Li are slash-and-burn agriculture and hunting. The culture of the Li is intermediate between the Thai and Indonesian peoples.