Abhidhamma: The third of the three “baskets” or collections comprising the Pali Canon, consisting of seven books devoted to standardizing the vocabulary of the teachings presented in the Suttas, or discourses, in the first basket.

Ajaan: A Thai word derived from the Pali term, ācariya: mentor or teacher.

Arahant: A “worthy one,” a person whose heart is freed from the fermentations (āsava) of sensuality, states of becoming, views, and ignorance, and who is thus not destined for further rebirth. An epithet for the Buddha and the highest level of his Noble Disciples.

Ariyadhana: Noble wealth, i.e., qualities that serve as capital in the quest for liberation: conviction, virtue, shame, compunction, erudition, generosity, and discernment.

Āsava: Fermentation; effluent. Four qualities—sensuality, views, becoming, and ignorance—that bubble up in the heart and flow out, leading to the flood of further becoming.

Avijjā: Ignorance; counterfeit awareness.

Brahmā: Inhabitant of the higher, non-sensual levels of heaven.

Buddho: Awake.

Deva: Literally, a “shining one.” A terrestrial or celestial spirit inhabiting a plane of sensual pleasure.

Dhamma: Event; phenomenon; the way things are in and of themselves; their inherent qualities; the basic principles that underlie their behavior. Also, principles of behavior that human beings ought to follow so as to fit in with the right natural order of things; qualities of mind they should develop so as to realize the inherent quality of the mind in and of itself. By extension, “dhamma” is used also to refer to any doctrine that teaches such things. Thus the Dhamma of the Buddha refers both to his teachings and to the direct experience of the quality—nibbāna—at which those teachings are aimed. In contexts where the term is used in a neutral sense in these talks, it has been left uncapitalized. Where used in a positive sense, it has been capitalized.

Dhātu: Property; element. The four physical properties are earth (solidity), water (liquidity), fire (heat), and wind (energy). The six properties include these four together with space and consciousness. (For a description of how the fire dhātu is related to the appearance and disappearance of a fire, see the discussion under nibbāna, below.)

Jhāna: Absorption in a physical sensation (rūpa jhāna) or in a mental notion (arūpa jhāna). Vitakka (directed thought), vicāra (evaluation), and pīti (rapture) are three of the five factors forming the first level of rūpa jhāna, the other two being sukha (pleasure) and ekaggatārammaṇa (singleness of preoccupation).

Kamma: Intentional actions that result in states of being and birth. Sometimes this term is also used to denote the results of such actions.

Khandha: Component parts of sensory perception, from which one’s sense of self is constructed: rūpa (physical sensations); vedanā (feelings of pleasure, pain, or neither pleasure nor pain); saññā (labels, concepts); saṅkhāra (mental fabrications, anything created by the mind); and viññāṇa (consciousness).

Māra: The personification of death, temptation, and any force that obstructs the practice of the path to Liberation.

Nibbāna (nirvāṇa): Liberation; the unbinding of the mind from greed, anger, and delusion, from physical sensations and mental acts. As this term is used to refer also to the extinguishing of fire, it carries connotations of stilling, cooling, and peace. (According to the physics taught at the time of the Buddha, the property of fire in a latent state exists to a greater or lesser extent in all objects. When activated, it seizes and sticks to its fuel. When extinguished, it is “unbound.”)

Nīvaraṇa: Hindrances to concentration—sensual desire, ill will, torpor & lethargy, restlessness & anxiety, and uncertainty.

Pāṭimokkha: The basic code of 227 rules followed by Theravāda Buddhist monks.

Saṅgha: The community of the Buddha’s followers. On the conventional level, this refers to the Bhikkhu Saṅgha, or Buddhist monkhood. On the ideal level, it refers to those of the Buddha’s followers, whether lay or ordained, who have practiced to the point of gaining at least “stream-entry,” the first of the transcendent qualities culminating in nibbāna.

Saṅkhāra: Fabrication—the forces and factors that fabricate things, the process of fabrication, and the fabricated things that result; all processes or things conditioned, compounded, or constructed by nature, whether on the physical or the mental level.

Sutta: Discourse.