Ev·er·est (ěv'ər-ĭst, ěv'rĭst) A mountain, 8,850 m (29,035 ft) high, of the central Himalaya Mountains on the border of Xizang (Tibet) and Nepal. The highest elevation in the world, it was first scaled in 1953 by members of an expedition including Sir Edmund Hillary and Tenzing Norgay.