TIBER

The spelling "Tiber" shows a possible combination of the Megrelian demonstrative pronoun (aka definite article) "თე" [te] with the root "iber", which is present in "Iberia" and in a whole group of related words and means "valley" in the Basque language.

UPDATE: The names of the Italian river Tiber are not that simple.

https://it.wikipedia.org/wiki/Tevere The ancient name is Albula. In the Georgian dictionary we find ალაბულა (and, by the way, we understand that it must be shortened to "albula", because Georgians do not like four-syllable words) meaning "pollution in water". But that's not all. The Etruscans called the river Tuvris (Θύβρις in ancient Greek). This is the Kartvelian genitive case of a certain "tuvri". Will we find "tuvri" in a Kartvelian dictionary? Yes, we will. In the Laz dictionary ტუვრი is "tomara", that is, "sack, bag". What is the semantic connection? Here we will ask the opinion of AI, here is his answer: Shape: The river's course might resemble a sack, perhaps with a wide, bulging section and a narrow outlet. Transportation: The river might have been historically used for transporting goods in sacks or bags. Gathering: The river's location could have been a place where people gathered things, like grain or fish, and stored them in sacks. Flooding: The river's flooding patterns might have resembled a sack filling up and then overflowing But that's not all. Another Etruscan name for the Tiber was "Rumon". This is Laz adjective from a certain "rumi". Will we find "rumi" among the Laz? Of course. In the Laz dictionary რუმი is ცივი (cold). By the way, it is believed that this is the same root as Rome (Rum).