The word yoga is derived from the root Yuj (युज्) which means to join. Connecting yourself to the God is yoga. The commentary of Vyasa on Yoga sutra, named Vyasbhashya, defines yoga as Samadhi - a state of intense concentration achieved through meditation. The composer of Yogasutra is Patanjali who was also a grammatician. The yoga of Patanjali is known as Patanjalyoga or Rajayoga. This Rajayoga is the theme of Patanjali’s entire scripture namely Yogasutram.