from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Located between mountains or mountain systems, especially lying between the Rocky Mountains and the Sierra Nevada or Cascade Range in the western United States.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Between mountains.
from The Century Dictionary and Cyclopedia
- Situated between mountains; intermontane.
inter- + mountain (Wiktionary)