contour vs thalweg

contour and thalweg both are nouns.

Word	Noun	Adjective	Verb	Adverb
contour	Yes	No	Yes	No
thalweg	Yes	No	No	No

As nouns, thalweg is a hyponym of contour; that is, thalweg is a word with a more specific, narrower meaning than contour:

contour (noun)	thalweg (noun)
any spatial attributes (especially as defined by outline)	a line following the lowest points of a valley
a feature (or the order or arrangement of features) of anything having a complex structure	the middle of the chief navigable channel of a waterway that forms the boundary line between states
a line drawn on a map connecting points of equal height

contour (verb)	thalweg (verb)
form the contours of