thalweg noun. ['tɑ:lvɛg, 'Ɵɑ:lwɛg] Also talweg. M19.
[German, from thal (now Tal) valley + Weg way.]
Physical Geography. The line of fastest descent from any point on land; esp. one connecting the deepest points along a river channel or the lowest points along a valley floor.

[TahlilGaran] English Dictionary ▲