noun Date: 1882 a line joining the waterfalls on numerous rivers that marks the point where each river descends from the upland to the lowland and the limit of the navigability of each river, the natural downhill course (as for skiing) between two points on a slope
FALL LINE
Meaning of FALL LINE in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012