诗 (shī) and
词 (cí) are two distinct classical forms.
诗 typically has fixed line lengths (Tang dynasty regulated verse, e.g. Li Bai, Du Fu).
词 is set to musical tune patterns with varying line lengths (peaked in Song dynasty, e.g. Su Shi, Li Qingzhao). Together
诗词 is the umbrella term for traditional Chinese poetic literature.
