Definition - What does Kriya Yoga mean?
Kriya yoga is an ancient type of meditation technique that, when practiced, is meant to rapidly accelerate one's spiritual progress.
Although practiced in India for centuries, the Kriya yoga meditation technique received worldwide attention after it was mentioned in the book, "Autobiography of a Yogi" by Paramahansa Yogananda. He is known as one of the modern founders of Kriya yoga and introduced the practice to the West in the 1920s.
Yogapedia explains Kriya Yoga
Kriya yoga is a meditation technique of controlling energy through pranayama and meditation, which speeds up the spiritual process of the aspirant. In 1861, the practice of Kriya yoga was revived by Mahavatar Babaji and passed through his disciple, Lahiri Mahasaya. Through Lahiri Mahasaya, the practice spread throughout India.
The practice of Kriya yoga is taught only through a guru-disciple relationship and after an initiation ceremony. Most practitioners of meditation spend time in self-study and practice until they are ready to be further initiated into the advanced practices of Kriya yoga. Beginning meditators are advised to use a mantra or word in order to focus their attention and progress into deeper meditation sessions.