interfluve

From interfluvial, “[lying] between streams”.^[1]

interfluve (plural interfluves)

1. (geology) The region of higher land between two connected river valleys.

• interfluvial

• Mesopotamia (from a feminine substantive form of the adjective μεσοποτάμιος (mesopotámios, “between rivers”), from the Ancient Greek μέσος (mésos, “between”) + ποτᾰμός (potamós, “river”) + -ιος (-ios); see more detailed etymology there)