fall line

noun

1. an imaginary line, marked by waterfalls and rapids, where rivers descend abruptly from an upland to a lowland.

2. Fall Line, (in the eastern United States) the imaginary line between the Piedmont and the Atlantic coastal plain.

3. Skiing.,  the path of natural descent from one point on a slope to another.

fall line

¹

noun

1. skiing the natural downward course between two points on a slope

2. the edge of a plateau

Fall Line

²

noun

1. a natural junction, running parallel to the E coast of the US, between the hard rocks of the Appalachians and the softer coastal plain, along which rivers form falls and rapids

fall line

1. A line connecting the waterfalls of nearly parallel rivers that marks a drop in land level.

Word History and Origins

Origin of fall line¹

An Americanism dating back to 1880–85