Tamil prosody defines several metres in six basic elements[1] covering the various aspects of rhythm.
It is based on a basic metrical unit named acai which forms the basis for all the important classical metres of Tamil.
[2] The third stage is marked by the gradual coming together of poetry and music starting with the use of fixed melody types (paṇ) in Shaiva and Vaishnava Bhakti texts.
The final stage appears with the introduction of free verse and prose-poetry in the early 20th century.
Other elements include todai (toṭai, alliteration) and vannam (vaṇṇam, "rhythmic effect", lit.