Yantra: A Tantric diagram or chart. Yin-Yang: Chinese symbol for the Laws of Polarity and Synthesis. Yoga: Literally means “yoke” or discipline. With no qualifying adjective, usually refers to Hatha Yoga (discipline of the body). A technique for achieving physical and mental strength and harmony. It builds flexibility, strength and inner-harmony. Yggdrasil The Norse tree which held up the world and the heavens; its roots led to the underworld. It provided the complex network of the universe. Yule: Decemebr 21, usually, the basis for Christmas Yule Log The traditional log burned at Christmas ceremonies which most likely came from a pagan tradition for Yule celebration.