In ancient times, the term “Annamalai” meant an inaccessible mountain. The word “Thiru” was prefixed to signify its greatness, and coupled with the two terms, it is called Tiruvannamalai. The main deity of the temple is Annamalaiyar and Unnamalai Amman. Shiva is worshiped as Arunachalesvara or Annamalaiyar, and is represented by the lingam, with his idol referred to as Agni lingam.
The temple is very unique as it is one among pancha bhooda stalam and sung by saiva kuravargal. The annamaliayar kovil was built before 1100 years and the architecture of the temple has its contribution from various kingdom from Cholas, Pandias, Sambuvarayars Posalas, Vijayanagar kings, Nayaks, Nagarathargal, Cheftains and Zamindars. And this is believed to be the largest temple in the world dedicated to Shiva.