Middle Way (Tib. དབུ་མ་, Skt. madhyamāpratipad) can refer specifically to the Madhyamika school or, more generally, to the Buddha's teachings as a whole, which present a path that avoids the two extremes of eternalism and nihilism.
Middle Way in the Sutrayana
In the Dhammacakkappavattana Sutta in the Pali Canon, the first teaching the Buddha gave after his enlightenment which sets forth the four noble truths, he speaks of the Middle Way, the path of practice that avoids the two extremes of sensual indulgence on the one hand, and severe asceticism on the other. He identifies this way specifically as the noble eightfold path.