(Pāli; Sanskrit: tṛ́ṣṇā तृष्णा IPA: [tr̩ʂɳaː] ) is an important concept in Buddhism, referring to "thirst, desire, longing, greed", either physical or mental. It is typically translated as craving, and is of three types: kāma-taṇhā (craving for sensual pleasures), bhava-taṇhā (craving for existence), and vibhava-taṇhā (craving for non-existence). Taṇhā appears in the Four Noble Truths, wherein arises with, or exists together with, dukkha (dissatisfaction, "standing unstable") and the cycle of repeated birth, becoming and death (saṃsāra). Taṇhā is a Pali word, derived from the Vedic Sanskrit word tṛ́ṣṇā (तृष्णा), which originates from the Proto-Indo-Iranian *tŕ̥šnas, which is related to the root tarś- (thirst, desire, wish), ultimately descending from Proto-Indo-European *ters- (dry). The word has the following Indo-European cognates: Avestan taršna (thirst), Ancient Greek térsomai (to dry), Lithuanian troškimas (thirst, desire), Gothic þaursus (dry), Old High German durst (thirst), English thirst. The word appears numerous times in the Samhita layer of the Rigveda, dated to the 2nd millennium BCE, such as in hymns 1.7.11, 1.16.5, 3.9.3, 6.15.5, 7.3.4 and 10.91.7. It also appears in other Vedas, wherein the meaning of the word is "thirst, thirsting for, longing for, craving for, desiring, eager greediness, and suffering from thirst". In the second of the Four Noble Truths, the Buddha identified as arising together with dukkha (unease, "standing unstable"). Taṇhā, states Walpola Rahula, or "thirst, desire, greed, craving" is what manifests as suffering and rebirths. However, adds Rahula, it is not the first cause nor the only cause of dukkha or saṃsāra, because the origination of everything is relative and dependent on something else. The Pali canons of Buddhism assert other defilements and impurities (kilesā, sāsavā dhammā), in addition to taṇhā, as the cause of Dukkha. Taṇhā nevertheless, is always listed first, and considered the principal, all-pervading and "the most palpable and immediate cause" of dukkha, states Rahula.