A tritina is a 10-line poem consisting of three three-line stanzas and a single line.
The three words that end each of the lines of the first stanza of the tritina are repeated in a different order at the end of lines in each of the subsequent two stanzas.
The word that is at the end of the lines in the first stanza is repeated at the ends of the lines in the other two stanzas, but in a different order. The first line in the second and third stanzas ends with the same word that is at the end of the line in the stanza before it. All three words are used in the final — 10th —line.