Etymology and nomenclature
Shiva (IAST: śiva, Tamil: சிவன், Sanskrit: शिव) literally means kind, friendly, gracious, or auspicious. As a proper name, it means "The Auspicious One".
The word Shiva is used as an adjective in the Rig Veda, as an epithet for several Rigvedic deities, including Rudra. The term Shiva also connotes "liberation, final emancipation" and "the auspicious one", this adjective sense of usage is addressed to many deities in Vedic layers of literature. The term evolved from the Vedic Rudra-Shiva to the noun Shiva in the Epics and the Puranas, as an auspicious deity who is the "creator, reproducer and dissolver".
The Sanskrit word śaiva or Shaiva means "relating to the god Shiva", while the related beliefs, practices, history, literature and sub-traditions constitute Shaivism.
Some authors associate the name Siva with the Tamil word śivappu meaning "the Red one" in Tamil and this tallies with the description of Rudra who is also called Babhru (brown, or red) in the Rigveda.