Sopadhi sesa
This is Nibbana, which is also called Nibbana with corporal remainder (sopadhi-sesa-nibbana).
The meaning of Nibbana is perfect peace or tranquility, or an eternally happy and joyous state in which wisdom, happiness and virtue are perfectly achieved.
Buddhists view such a sate as only attainable by holy ones, thus can not be judged by experienced conceptions like existence, non-existence, coming and going etc.
It is an inconceivable state emancipation.
As I mentioned above, Nibbana can be interpreted as passing away.
Actually, Sakyamuni attained Nibbana and became a Buddha at the age of 30, yet his corporal body remained as the residual fruit of his former illusion and kamma.
This is Nibbana with remainder (sopadhi-sesa-nibbana).
It was not until his death at the age of 80, that he entered Nibbana without remainder (Nirupadhi-sesa-nibbana).