that are less reduced than the basic set (in modern terms, the zero grade), but more reduced than the vowels (in modern terms, the lengthened grade). As an example, ṛ, i, u are basic (zero-grade) vowels, with corresponding (full-grade) vowels ar, e, o and (lengthened-grade) vowels ār, ai, au. (This is more understandable once it is realized that, at an earlier stage of development, Sanskrit e and o were ai and au, and Sanskrit ai and au were āi and āu.) Guna corresponds to what is now termed the full grade in Indo-European ablaut. Another orthography and phonology concept related to Guna is Vṛddhi. Ayurveda In the terminology of Ayurveda (traditional medicine), guṇa can refer to one of twenty fundamental properties which any substance can exhibit, arranged in ten pairs of antonyms, viz. heavy/light, cold/hot, unctuous/dry, dull/sharp, stable/mobile, soft/hard, non-slimy/slimy, smooth/coarse, minute/gross, viscous/liquid. Guna is also a concept in Ayurvedic medicine, as a system to assess conditions and diets. For this reason Triguna and tridosha are considered to be related in the traditions of Ayurveda. See also Guṇa (Jainism), the concept in Jainism Jain (Satvika) Maya Nirguna Brahman, Saguna Brahman References Further reading Narain, Harsh. "Finding an English Equivalent for 'Guna'". Philosophy East and West 11.1 (1961): 45. External links Sattva, Rajas & Tamas From The Mahabharata Guna debate 1, One of many in The Vedanta-Sutras, Ramanuja's views, George Thibaut (Translator) Guna debate 2, One of many in The Vedanta-Sutras, Shankara's views, George Thibaut (Translator) Chapter 2: Each is Great in His Own Place Sattva, Rajas & Tamas – gunas and Karma Yoga, Vivekananda Sattva, Rajas & Tamas From a Shamanic perspective Guna