interfluve
Concise Oxford English Dictionary © 2008 Oxford University Press:
interfluve /ˈɪntəfluːv/
▶noun Geology a region between the valleys of adjacent watercourses.
– derivatives
interfluvial adjective.
interfluvial adjective.
– origin early 20th cent.: back-formation from interfluvial.
'interfluve' also found in these Oxford entries:

