Definition - What does Kapalbhati mean?
Kapalbhati is an element of the yogic body cleansing system that is known as shatkarma or shatkriya. This Sanskrit word is derived from the root words kapal, meaning “skull," and bhati, which is best translated as “illuminating” or “shining.”
The basic idea of kapalbhati is that the brain and all parts of the skull are cleansed through short but strong exhalations of air.
Yogapedia explains Kapalbhati
There are three different types of kapalbhati. In the case of vatakrama kapalbhati, exhalation is forced while inhalation is natural and passive. Vyutkrama kapalbhati sees water sniffed in through the nose and then spat out through the mouth. Finally, sheetkrama kapalbhati is when water is taken in the mouth and then forced out through the nose.
This practice is carried out in order to cleanse the nasal passages and respiratory system, which prepares the practitioner for kapalbhati pranayama (skull shining breath) or any other of the various yogic breathing techniques.