D defs.my
Entry 3 senses Webster, 1913

Mountainous

/moun'-tən-əs/ · Moun·tain·ous · IPA /ˈmaʊn.tɪ.nəs/
01 a. Full of, or containing, mountains; as, the mountainous country of the Swiss.
  1. 1.
    Full of, or containing, mountains; as, the mountainous country of the Swiss.
  2. 2.
    Inhabiting mountains.[Obs.]
  3. 3.
    Large as, or resembling, a mountain; huge; of great bulk; as, a mountainous heap.