rounded, snow-covered massif of the Pennine Alps lying on the frontier between Switzerland and Italy, rising southeast of Zermatt, Switz. Ten summits in this huge mountain mass are distinguished by name. Four of them (Nordend, Zumsteinspitze, Signalkuppe 【Punta Gnifetti】, and Parrotspitze) lie on the frontier; five lower peaks are on the Italian slope. The 10th, Dufourspitze (15,203 ft 【4,634 m】), is the highest peak of the mass and of Switzerland, rising on a buttress west of the frontier ridge. Gorner and several other glaciers on the north slope meet near Zermatt at the head of the Mattervisp River Valley. A laboratory for nuclear research has been established on the Italian slope. The name Monte Rosa is derived from an Aostian patois word roëse, meaning “glacier.”