This term refers to the state of having left samsara, the circle of rebirth. The literal meaning of nirvana is extinction or blowing off, in contrast to affliction, which is burning like fire. It refers to the attainment of a purified state where one attains enlightenment and eradicates affliction, birth, and death. This is the primary goal for all Buddhist practices. There are two types of nirvana: with and without remainder. In “nirvana with remainder,” the practioner’s body, owing to the karmic results of his or her previous lives, remains even after the enlightenment. In “nirvana without remainder,” where the karma has been totally eliminated, and his or her physical form and consciousness are brought to an end, he or she is delivered from samsara for good. Mahayana scriptures reinvent the notion of “nirvana” by interpreting it as the perfect comprehension of the ultimate reality, so to proclaim that essentially nirvana and the mundane world are not exclusive to each other.
Buddhas are, therefore, neither found to be present in the mundane world nor to be in the state of nirvana. They attain enlightenment through realizing their own true mind, which is formless. So how can a formless thing be either present or absent? Transformations of Buddha’s body are only shown according to the occasion to those sentient beings with prepared state of mind. Hence, all the manifestations of Buddhas are nothing but the images in the sentient beings’mind. (Shi Yanshou: Records of the Source-mirror)