Svami Desikan in his Navamanimalai, has said “pandhu, kazhal, ammAnai, Usual, Esal, paravu, namamaNimAlai…” – What are ammAnai, Usual, Esal, pravu?

In the commentary for Navamanimalai, “paravu” is meant as “that which is celebrated by all.”
Pandhu, kazhal, ammAnai, Usual and Esal are 5 prabandhams, which have been lost and are non-existent now; only Navamanimali alone is available for us.