What does "thalweg" mean?

The line that connects the lowest points in a valley or river channel, and thus the line of fastest flow or deepest water along a river’s course.

What is a synonym for "thalweg"?

Common synonyms include: deepest channel, line of minimum elevation, main channel.

/ˈtɑl.vɛɡ/ noun

noun ·Rare ·Advanced level

Noun

1
The line that connects the lowest points in a valley or river channel, and thus the line of fastest flow or deepest water along a river’s course.
2
a line following the lowest points of a valley wordnet
3
the middle of the chief navigable channel of a waterway that forms the boundary line between states wordnet

Borrowed from 19th century German Thalweg, from Thal (“valley”) + Weg (“way, course”).