Linga is the Sanskrit term in the Samkhya system for the characteristic "mark" of the individual reincarnating entity. Sarira (Sanskrit) is derived from the verbal root sri to protect, shelter, enter into. The Linga Sarira; etherical shelter is the subtle body or vehicle of consciousness in later Samkhya, Vedanta, and Yoga. In Theosophy the Linga Sarira or Linga Sharira became the name for the invisible double of the human body, the Sthula Sarira ; also referred to as the etheric body, etheric double, astral body (which has two different meanings), doppelganger (twin), bioplasmic body, pranamayakosa, and so on in New Age writings.