
1) Sanskrit text 2) Yoga texts and documentation
Found on
https://www.crosswordclues.com/clue/upanishads

The second great collection of ancient sacred Hindu texts, the Upanishads followed the Vedas and set forth doctrines such as Self-realization, Yoga, meditation, karma and reincarnation, which were kept veiled under the symbols of the older texts.
Found on
http://www.encyclo.co.uk/local/22150

A collection of texts at the end of the Vedas that record early Hindu speculations on Brahman, atman and moksha. These texts are very influential to Hindu thought (Esposito et al. 2012a
Found on
http://www.thearda.com/learningcenter/religiondictionary.asp

A collection of some of the most influential Hindu texts, dealing with philosophy and mysticism. Where the Vedas were concerned primarily with the rituals and sacrifices, the Upanishads focused on the relationship between the Supreme God (Brahaman), deities, and man.
Found on
http://www.thebuddhagarden.com/hindu-glossary.html

The Upanishads, dating largely from the 8th to the 6th centuries BCE, are the “wisdom literature” of the Vedas. Most Upanishads take the form of dialogues between teachers and students. They turn from the rites of the fire altar that had been the main focus of discussion in the earlier Vedic literature to the question of the deeper, inner meani...
Found on
https://pluralism.org/hinduism-glossary-terms

A Hindu shruti text. Literally translates as ‘sit down nearby’. The final book of the Vedas characterised by its mystical and philosophical speculation of the nature of the Self and Ultimate Reality.
Found on
https://www.aqa.org.uk/resources/religious-studies/as-and-a-level/a-level/t

Pronounced “oo-PAAN-ish-ud.” The Upanishads are the final sections of each of the four Vedas, or Hindu scriptures. These texts are spiritual dialogues in which teachers and students discuss ultimate questions of human existence.
Found on
https://www.deshvidesh.com/glossary-of-hinduism-terms/

A collection of some of the most influential Hindu texts, dealing with philosophy and mysticism. Where the Vedas were concerned primarily with the rituals and sacrifices, the Upanishads focused on the relationship between the Supreme God (Brahaman), deities, and man.
Found on
https://www.thebuddhagarden.com/hindu-glossary.html
No exact match found.