Tukdam

Tukdam (Wyl. thugs dam) is an honorific term for meditative practice and experience that is frequently used to refer to the period following the death of a great master, during which time they are absorbed in luminosity. As Sogyal Rinpoche describes it in The Tibetan Book of Living and Dying:

A realized practitioner continues to abide by the recognition of the nature of mind at the moment of death, and awakens into the Ground Luminosity when it manifests. He or she may even remain in that state for a number of days. Some practitioners and masters die sitting upright in that state for a number of days. Some practitioners and masters die sitting upright in meditation posture, and others in the “posture of the sleeping lion.” Besides their perfect poise, there will be other signs that show they are resting in the state of the Ground Luminosity: There is still a certain color and glow in their face, the nose does not sink inward, the skin remains soft and flexible, the body does not become stiff, the eyes are said to keep a soft and compassionate glow, and there is still a warmth at the heart. Great care is taken that the master’s body is not touched, and silence is maintained until he or she has arisen from this state of meditation.