The word appears in the ancient Principal Upanishads of Hinduism, as well as the "Bhagavad Gita". For example, verse 3.5 of the "Maitri Upanishad" and verse 2.2.9 of the "Mundaka Upanishad" contain the word "rāga". The "Mundaka Upanishad" uses it in its discussion of soul (Atman-Brahman) and matter (Prakriti), with the sense that the soul does not "color, dye, stain, tint" the matter. The "Maitri Upanishad" uses the term in the sense of "passion, inner quality, psychological state". The term "rāga" is also found in ancient texts of Buddhism where it connotes "passion, sensuality, lust, desire" for pleasurable experiences as one of three impurities of a character. Alternatively, "rāga" is used in Buddhist texts in the sense of "color, dye, hue".