(Sanskrit, literally "power or force of life") The energy that results from positive, pure spiritual transmutation, achieved through very specific techniques.

"Sublimation is not a matter of suppression or repression, but a positive, dynamic, conversion process. It is the process of controlling the sex energy, conserving it, then diverting it into higher channels, and finally, converting it into spiritual energy or Ojas Sakti. The material energy is changed into spiritual energy, just as heat is changed into light and electricity. Just as a chemical substance is sublimated or purified by raising the substance through heat into vapour which again is condensed into solid form, so also, the sexual energy is purified and changed into divine energy by spiritual Sadhana." - Swami Sivananda, Brahmacharya

"The Sanskrit term Ojas means “transmuted sexual energy,” a type of Christic force. The semen is transmuted by means of Maithuna into subtle vapors, and these in turn convert themselves into energies that bipolarize in order to rise through Ida and Pingala up to the brain. To be converted into Ojas (Christic force) the semen must become “cerebrated.”  In order to be charged with Ojas (Christic force), the brain must become “semenized.””  - Samael Aun Weor, The Doomed Aryan Race