[ tahl-veg, -veyk ]
/ ˈtɑl vɛg, -veɪk /
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a line, as drawn on a map, connecting the lowest points of a valley.
Chiefly International Law. the middle of the main navigable channel of a waterway that serves as a boundary line between states.



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Origin of thalweg

1860–65; <German, equivalent to Thal, now obsolete spelling of Tal valley (cognate with dale) + Wegway1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021
  • The thalweg has been frequently confirmed as the accepted boundary where no conventions to the contrary existed.

    International Law|George Grafton Wilson and George Fox Tucker

British Dictionary definitions for thalweg



/ (ˈtɑːlvɛɡ) /

noun geography rare

the longitudinal outline of a riverbed from source to mouth
the line of steepest descent from any point on the land surface
C19: from German, from Thal valley + Weg way, path
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for thalweg

[ tälvĕg′ ]

The line defining the lowest points along the length of a river bed or valley, whether underwater or not.
A subterranean stream following a course similar to that of an overlying surficial stream.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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