sub-mountain
/ˈsʌbˌmaʊntɪn/Geography
noun
A peak or upland area that is adjacent to a mountainous region; a peak that is lower than a mountain. Chiefly in plural.
adjective
Attributive Of the nature of a sub-mountain; relating to or characteristic of sub-mountains.
Origin
Late 18th century; earliest use found in William Tooke (bap. 1744, d. 1820), writer and translator. From sub- + mountain.