The Panchakshara actually means “5 letters” in Sanskrit and refers back to the 5 holy letters Na, Ma, Śi, Vā and Ya. That is prayer to Lord Shiva, and is related to Shiva’s Mantra Om Namah Shivaya , of which Namah Shivaya can be known as the Panchakshari Mantra.
The good Shri Adi Sankaracharya (thought-about an incarnation of Shiva Himself) is the writer of this stotra.