- a series of more or less connected mountains ranged in a line.
- a series of mountains, or of more or less parallel lines of mountains, closely related, as in origin.
- an area in which the greater part of the land surface is in considerable degree of slope, upland summits are small or narrow, and there are great differences in elevations within the area (commonly over 2,000 feet, or 610 meters).
- a series of adjoining mountains or of lines of mountains of similar origin
