Dhyana (Sanskrit) can refer to a form of meditation or to an absorbed state of mind brought about by meditation. In particular, dhyana refers to the four states of absorption, sometimes called the "four dhyanas."
When the meditator reaches the first dhyana, passions, desires and unwholesome thoughts (see akusala) are released, and the meditator feels joyful interest and a sense of well-being.
In the second dhyana, intellectual activity fades and is replaced by tranquility and one-pointedness of mind. Joyful interest and sense of well-being are still present.
In the third dhyana, joy fades and is replaced by equanimity (upekkha).
In the fourth dhyana, all sensation ceases and only mindful equanimity remains.