arupa

Arupa is a term used in Sanskrit and Pali to denote “formless” or “without form.” Etymologically it combines a- (not) with rupa (form). In Buddhist thought, arupa denotes both a set of meditative attainments and the corresponding realms. The arupa-jhānas, or formless absorptions, are states beyond the rupa-jhānas (form jhānas) and are described as deep concentrations in which perception and feeling become subtler. The standard enumeration identifies four arupa-jhānas: 1) infinite space (ākāsānañcāyatana), 2) infinite consciousness (viññāṇañcāyatana), 3) infinite nothingness (ākiñcaññāyatana), and 4) infinite neither perception nor non-perception (nevasaññā-nāsaññāyatana). Some sources also describe a further state beyond these, but traditional lists present the four. In Buddhist cosmology, arupa-lokas are the formless realms inhabited by beings whose existence rests on the arupa-jhānas.

In other Indian traditions, arupa appears as a broader category of the formless as opposed to form, though schemes vary and arupa is not always used as a formal label. In modern usage, the term is commonly encountered in translations of Buddhist texts as a technical designation for immaterial states. See also: arupa-loka, rupa, jhana, formless realm.