Shiva the name of the Lord is a mantra. The meaning of Shiva is "One Who is all Bliss and the giver of happiness to all." Lord Shiva is considered as one of the Trinity of Hindu pantheon (Brahma, Vishnu, and Shiva). He is the supreme God in the Saiva religion (one among the six cults or religion or Shanmatha established by Adi Sankaracharya) or Saiva Siddhanta tradition of Hinduism. His name is referred as Rudra in Rig veda. ‘Although classically applied to the Absolute Brahman, Shiva can also refer to God (Ishwara) in His aspect of Dissolver and Liberator (often mistakenly thought of as "destroyer")’.
The icon Shiva Lina is considered as the abstract form of Lord Shiva. Another icon Nataraja represent Him as Lord of Dance. The Moola Mantra of Lord Shiva is Om Namashivaya. It is known as ‘Panchaksharam’ of five letter mantra. It forms exactly the central part of Sri Rudram and Sri Rudram forms the center part of Yajur Veda.
Om Tatpuruṣhaya Vidmahe