Kriyā

most commonly refers to a "completed action", technique or practice within a yoga discipline meant to achieve a specific result.

Etymology

is a Sanskrit term, derived from the Sanskrit root, meaning 'to do'. ' means 'action, deed, effort'. The word karma is also derived from the Sanskrit root ' कृ, meaning 'to do, make, perform, accomplish, cause, effect, prepare, undertake'. Karma is related to the verbal Proto-Indo-European root kwer- 'to make, form'.
The root is common in ancient Sanskrit literature, and it is relied upon to explain ideas in Rigveda, other Vedas, Upanishads, Puranas, and the Hindu epics.

Practices

The Yoga Sutras of Patanjali 2.1 defines three types of, namely tapas, svadhyaya, and Ishvarapranidhana|.
The yogic purifications or shatkarmas are sometimes called the Shatkriyas.
The Kriya Yoga school, established by Yogananda, is centered on pranayama techniques.