Sanjna means consciousness. In the Puranas it is stated that Sanjna is the daughter of Viswakarma. She married Surya, or the Sun and had three children. The two sons and a daughter were Manu (Vaivaswata), Yama, and the goddess Yami (or the Yamuna River). Unable to endure the fervour of her lord, Sanjna gave him, her own Chhaya (shadow) as his handmaid, and went to the forests to practise devout exercises.
The Sun thought Chhaya to be his wife Sanjna and begot by her three other children. They were two sons Sanaischara (Saturn), Savarni, and a daughter Tapati (the Tapti River). Chhaya, on one occasion, being offended with Yama, the son of Sanjna, denounced an imprecation upon him, and thereby revealed to Yama and to the Sun that she was not his real wife Sanjna but the shadow of her. Being further informed by Chhaya that Sun's wife Sanjna had gone to the wilderness to meditate.
The Sun with his third eye saw Sanjna, meditating and engaged in austerities, in the figure of a mare in the region of North Kuru. Sun transformed himself into a horse and rejoins his wife. Sun and Sanjna had three other children with this union, the two Asvins and Revanta. Then Sun brought Sanjna back to his own dwelling. To diminish Sun's intensity, Viswakarma placed the luminary on his lathe, to grind off some of his effulgence; and in this manner reduced it an eighth, for more than that was inseparable.