Om Namah Shivaya (Devanagari: ॐ नमः शिवाय; IAST: Oṃ Namaḥ Śivāya) is one of the most popular Hindu mantras and the most important mantra in Shaivism. Namah Shivaya means "O salutations to the auspicious one!", or "adoration to Lord Shiva". It is called Siva Panchakshara, or Shiva Panchakshara or simply Panchakshara meaning the "five-syllable" mantra (viz., excluding the Om) and is dedicated to Shiva. This Mantra appears as 'Na' 'Ma' 'Śi' 'Vā' and 'Ya' in the Shri Rudram Chamakam which is a part of the Krishna Yajurveda and also in the Rudrashtadhyayi which is a part of the Shukla Yajurveda.
The five-syllabled mantra (excluding the Oṁ) may be chanted by all persons including śūdras and cāṇḍalas; however the six-syllabled mantra (with Oṁ included) may only be spoken by dvijas.