Cí (pronounced [tsʰǐ]; Chinese: 詞) is a type of lyric poetry in the tradition of Classical Chinese poetry. Cí use a set of poetic meters derived from a base set of certain patterns, in fixed-rhythm, fixed-tone, and variable line-length formal types, or model examples. The rhythmic and tonal pattern of the ci are based upon certain, definitive musical song tunes. They are also known as Changduanju (長短句 / 长短句, "lines of irregular lengths") and Shiyu (詩餘 / 诗馀, "the poetry is besides Shi").
Typically, the number of characters in each line and the arrangement of tones were determined by one of around 800 set patterns, each associated with a particular title, called cípái (詞牌). Originally, they were written to be sung to a tune of that title, with a set rhythm, rhyme, and tempo. Therefore, the title may have nothing to do with its content. Indeed, several ci often shared the same title. The titles did not refer to the content, but rather their shared rhythmic and tonal patterns. Some cí would have a "subtitle" or a commentary, sometimes as long as a paragraph, indicating the content. Sometimes, for the sake of clarity, a cí is listed under its title, followed by its first line.
Cí most often express feelings of desire, often in an adopted persona, but the greatest exponents of the form (such as Chen Weisong 陳維崧/陈维崧 and Su Shi 蘇軾/苏轼) used it to address a wide range of topics.