The dravya in Jainism are fundamental entities, called astikaya (literally, collection that exists). They are believed to be eternal, and the ontological building blocks that constitute and explain all existence, whether perceived or not. According to both Śvētāmbara and Digambara traditions of Jainism, there are six eternal substances in existence: Soul (jiva), Matter (pudgala), Space (akasha), motion (Dharma) and rest (Adharma) and "Time" (kala). In both traditions, the substance of space is conceptualized as "world space" (lokakasha) and "non-world space" (alokiakasha). Further, both soul and matter are considered as active ontological substances, while the rest are inactive. Another categorization found in Jain philosophy is jiva and ajiva, the latter being all dravya that is not jiva.
Out of the six dravyas, five except time have been described as astikayas, that is, extensions or conglomerates. Since like conglomerates, they have numerous space points, they are described as astikaya. There are innumerable space points in the sentient substance and in the media of motion and rest, and infinite ones in space; in matter they are threefold (i.e. numerable, innumerable and infinite). Time has only one; therefore it is not a conglomerate. Hence the corresponding conglomerates or extensions are called—jivastikaya (soul extension or conglomerate), pudgalastikaya (matter conglomerate), dharmastikaya (motion conglomerate), adharmastikaya (rest conglomerate) and akastikaya (space conglomerates). Together they are called pancastikaya or the five astikayas.