A tercet is composed of three lines of poetry, forming a stanza or a complete poem.
English-language haiku is an example of an unrhymed tercet poem. A poetic triplet is a tercet in which all three lines follow the same rhyme, a a a; triplets are rather rare; they are more customarily used sparingly in verse of heroic couplets or other couplet verse, to add extraordinary emphasis.
Other types of tercet include an enclosed tercet where the lines rhyme in an a b a pattern and terza rima where the a b a pattern of a verse is continued in the next verse by making the outer lines of the next stanza rhyme with the central line of the preceding stanza, b c b, as in the terza rima or terzina form of Dante Alighieri's Divine Comedy. There has been much investigation of the possible sources of the Dantesque terzina, which Benedetto Croce characterised as "linked, enclosed, disciplined, vehement and yet calm". William Baer observes of the tercets of terza rima, "These interlocking rhymes tend to pull the listener's attention forward in a continuous flow.... Given this natural tendency to glide forward, terza rima is especially well-suited to narration and description".
Früher, da war ich eine Currywurst
Die Boulette sagte guten Tag
Sagte guten Tag (das Fett, das Fett)
Früher, da war ich eine Currywurst ...