n. A hill at the base of a mountain or mountain range.
the GNU version of the Collaborative International Dictionary of English
n. A low hill at the foot of higher hills or mountains.
The Century Dictionary and Cyclopedia
n. A distinct lower part of a mountain; one of the hills or minor elevations of a mountain range which lie next the valley and form the transitions between that and the higher portions: most commonly in the plural: as, the foot-hills of the Sierra Nevada.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a relatively low hill on the lower slope of a mountain
Word Usage
"The lower third of the mountains, that is, the foothill section, is only tree-dotted."