Bilvaor Vilvam leaf is the leaf of the Koovalam tree. This leaf is trifoliate and is believed that these three signify for the three eyes of Lord Shiva by some while some signify it to be the three lords, Brahma, Vishnu and Shiva. Vilvam leaf is dear to Lord Shiva. This sacred leaf has descriptions in theShiva Purana and Skanda Purana. Additionally few devotes believe Vilvam leaf to be originated from Goddess Mahalakshmi.
The popular Sanskrit Shiva shloka verse:
Tridalam TrigunakaramTrinetrancha Triyaayudham
Trijanma Paapa SamharamEka Bilvam Shivarpanam
Describes the importance of worshipping Lord Shiva in the form of Lingam and explains as to how with the offering of a Bilva leaf, one can wash away their skins and attain Moksha or liberation.
This sacred leaf is of demand during Mahashivaratri and during many religious rituals of the Hindus.