The Collaborative International Dictionary of English v.0.48:
massif \massif\ n. (Geol.) A block of the earth's crust bounded by faults and shifted to form peaks of a mountain range. [WordNet 1.5]WordNet (r) 3.0 (2006):
massif n 1: a block of the earth's crust bounded by faults and shifted to form peaks of a mountain range