From Rigpa Wiki
- bliss (Tib. བདེ་བའི་ཉམས་, Wyl. bde ba'i nyams),
- clarity (Tib. གསལ་བའི་ཉམས་, Wyl. gsal ba'i nyams), and
- absence of thoughts (Tib. མི་རྟོག་པའི་ཉམས་, Wyl. mi rtog pa'i nyams).
Sogyal Rinpoche writes:
- As you continue to practise [meditation], you may have all kinds of experiences (Tib. nyam), both good and bad. Just as a room with many doors and windows allows the air to enter from many directions, in the same way, when your mind becomes open, it is natural that all kinds of experiences can come into it. You might experience states of bliss, clarity or absence of thoughts.
- In one way these are very good experiences, and signs of progress in meditation.
- By themselves they are good experiences, but if you get attached to them they become obstacles. Experiences are not realization in themselves; but if we remain free of attachment to them, they become what they really are, that is, materials for realization. 
Furthermore, it is said that being attached to these kinds of experience causes the practitioner to be further reborn in samsara—in places devoid of any opportunity to practise the Dharma, respectively:
- attachment to the experience of bliss can lead to a rebirth in one of the six heavens of the desire realm, or in the preta realm;
- attachment to the experience of clarity can lead to a rebirth in the heavens of the form realm, and
- attachment to the experience of absence of thought can lead to a rebirth in the heavens of the formless realm, or in the animal realm.
- Sogyal Rinpoche, The Tibetan Book of Living and Dying, revised and updated edition, Harper San Francisco, 2002, page 76.