Two levels of Truths (2)

Following from the previous post, from the same book, on page 87...

Identity of Nirvana and Samsara

The uncompromising spirit of Mahayana logic tears down all forms of separation, even that which distinguishes nirvana from samsara. In terms of absolute truth, nirvana is samsara, and vice-versa. There is no split or separation. This, needless to say, throws the ordinary world into a new light: it is indeed the transcendental world of true reality, the world of buddhas and bodhisattvas, though our defilements prevent us ordinary mortals from seeing it as such.

....Now, what does Mahayana refers to as "nirvana"? I don't think it is the same as Theravada's interpretation of "nibbana".