A Tritina is a type of poem that consists of tercets. A Tercet is three lines of a verse that rhyme with one another. They may also rhyme by rhyming with another tercet. A Tritina has three as well as a final line. This totals a Tritina at ten lines. A Tritina repeats the final words of the tercet into the other two, so all three consist of the same final word and rhyme. However, the end words are rearranged in a specific order so the first would be 1/2/3. The second one would be 3/1/2. The final tercet would be 2/3/1. The concluding line in a Tritina would then incorporate all the final words of the tercets, once again specifically in the order of 1/2/3.

A Tritina does not need a specific syllable count in order to be one, but it is recommended that a decent and consistent scheme would be included in order to provide a better flow. 

The Tritina is a modern form created by cutting down the Sestina. Like a Sestina this form repeats the end words of each stanza. The form is made up of three triplets these use an end word order of 1-2-3,3-1-2,2-3-1. After the triplets comes an envoi constructed from a single line. All four end words must appear in this envoi in the order 1-2-3.

  1 2 3          - End words of lines in first tercet.
  3 1 2          - End words of lines in second tercet.
  2 3 1          - End words of lines in third tercet.
  (1 2 3)        - Words contained in the final line