Pentastich is a poetic form characterized by a five-line stanza. It is often used in haikus or other short forms of poetry. However, if you are looking to add variety to your poetry, there are other synonyms for pentastich that you can use. For example, you could use the term cinquain, quintain, or quintet. These words are all synonyms for pentastich and represent other forms of poetry that use five-line stanzas. By using these synonyms, you can add variety to your poems and express your creativity in new ways.