There are four stages of enlightenment, sotāpanna, sakadāgāmi and anāgāmi, in that order, one stage at a time, and enlightenment is completed at arahant.
A person at these four stages is an enlightened person, a person who has not left enlightenment and a saint. And they are members of the sangha.
Similar to, but different from, the four stages of jhāna. jhāna is the still mental state reached through samatha meditation. It is not ‘nirvana‘, which is reached through enlightenment, and should not be confused with it.
1st stage: Sotāpanna
The first stage is that of sotāpanna.
sota (ear) + āpanna (āpajjati: entered upon): “Hearer-enterer“: one who only heard about the Dhamma and entered the path of nirvana (Pali: Nibbāna) . Sotāpanna is also said to have “opened the eye of the Dhamma” (dhammacakkhu)
They will no longer be born in the animal womb, or hell realms; nor as a hungry ghost. The pathways to unfortunate rebirth destinations (duggati) have been closed to them.
“Sotāpanna” has dropped the first three fetters of the 10 fetters.
1. sakkāya-diṭṭhi : personality-belief
They have realized that whatever arises will cease (impermanence).
2. vicikicchā : sceptical doubt
Their conviction in the true Dhamma is unshakable.
The sotāpanna is said to attain an intuitive grasp of the dharma, this wisdom being called right view (sammā diṭṭhi) and has complete confidence in the Three Jewels: Buddha, Dhamma and Sangha.
3. sīlabbata-paramāsa : clinging to mere rules and ritual
They have not attachment to rites and rituals.
These are the only three things that disappear in sotāpanna. Moreover, they are all related to views, evil views and ignorance, greed and anger have not disappeared. So the angry character and the greedy mind have hardly changed yet. But only the helpless ignorance has disappeared, and since they know that everything is impermanent, there is a sense of resignation somewhere, and intense attachment has decreased.
A sotāpanna reaches arahantship within seven rebirths upon opening the eye of the Dharma.
2nd stage: Sakadāgāmi
The second stage is that of the sakadāgāmī.
sakid (once) + āgāmin(returning): “Once-returner“: one who returns to another form of life in saṁsāra.
The second stage cannot be reached simply by hearing the Dhamma. The sakadagāmi is also a meditation practice, when they experience the second “I am not here, there is nothing” moment, even for a second.
They have cut off the first three chains with which the ordinary mind is bound , and significantly weakened the fourth and fifth.
4. greed (kāmacchanda)
Sensual desire:
5. anger (vyāpāda)
Ill will:
3rd stage: Anāgāmi
an(non) + āgāmin (returning): “Non-returner“: one who never return.
Anāgāmin is not reborn into the human world after death, but into the world of the pure abodes, where only anāgāmins reside. There they attain full enlightenment.
Anāgāmi is a partially enlightened person who has cut off the first five fetters that bind the ordinary mind.
4th stage: Arahant
The final stage is that of arahant, a fully awakened and enlightened person.
One who has gained insight into the true nature of existence and has achieved nirvana (Pali: nibbāna) and liberated from the endless cycle of rebirth.
They have abandoned all 10 fetters,