In the second chapter of the Yoga Sūtras, kriyā yoga is a preparatory discipline of austerity, study and devotion, which weakens the afflictions and makes absorption possible. In modern times the name was used by Paramahansa Yogananda’s tradition for a breath-based meditation technique.
Kriyā yoga
The yoga of action in the Yoga Sūtras: austerity, self-study and dedication to the Lord.
Also: Kriya yoga