The word Nirvana is a negative word. Literally it means 'blowing out the candle'.
Gautama Buddha used the word for the ultimate state of consciousness. He could have chosen some positive word, and in India there were many positive words for it. Moksha - freedom, liberation. Kaivalya - aloneness, absolute aloneness. Brahmmanubava - the experience of the ultimate. But he chose a strange term, which has never been used in a spiritual context: "blowing out the candle".
Thousands of times Buddha was asked, "Your word nirvana does not create in us an excitement, does not create in us a desire to achieve it. The ultimate truth, self-realisation, the realisation of God - all those create desire, a great desire. Your word creates no desire."
And Buddha said again and again, "That is the beauty of the word. All those words that create desire in you are not going to help you, because desire itself is the root cause of your misery. Longing for something is your tension. Nirvana makes you absolutely free from tension; there is nothing to desire".