Nirvana is a word about a candle going out. In Sanskrit, nirvāṇa means "blown out" or "extinguished." It is built from nir-, "out," and the verb root vā, "to blow."
That image is the whole idea. In Buddhism, nirvana is the state reached when the fires of craving, hatred and delusion stop burning. Britannica calls it the oldest and most common name for the supreme goal of Buddhist practice. The Pali form, used in early Buddhist texts, is nibbāna.
The metaphor may have been a pointed choice. Wikipedia notes that older Vedic tradition treated fire as something good and sacred. Early Buddhists appear to have turned that around. For them, liberation meant the fire going out, not being fed.
The word is not only Buddhist. It is shared across Indian religions. In Jainism it names release from the bonds of karma. In Hindu texts such as the Bhagavad Gita, brahma-nirvāṇa means union with Brahman. That is a different idea from the Buddhist one, but the same word.
English borrowed it in 1836, according to Etymonline, in writing about "the condition of a Buddha." At first it meant the extinction of the individual self. The looser sense of "perfect bliss" or a state of total happiness is recorded from 1895. Today someone can be "in nirvana" over a good meal, far from the original sense of a self going out like a flame.
The Sanskrit root has distant English relatives. Etymonline traces vā to a Proto-Indo-European root, we-, "to blow." The same root gives wind, weather and, through Latin ventus, vent and ventilate. Etymonline also points out that a word-for-word Latin match for nirvana would be de-spiration, a breathing out.
The word gained a second life in 1988. A Washington state band that had played as Skid Row, Pen Cap Chew, Bliss and Ted Ed Fred settled on Nirvana. Kurt Cobain said he wanted a name that was "kind of beautiful or nice and pretty." He contrasted it with "a mean, raunchy punk name like the Angry Samoans." A British band already called Nirvana sued, and the case was settled out of court.