The Proto-Kartvelian word ṭab-
Word ṭab-
Meaning lake
Synonyms ṭba

Comments
Heinz Fähnrich, Surab Sardshweladse: Etymologisches Woerterbuch der Kartwel-Sprachen, 1995 Brill

Other words that might be of interest
lumb- ‘wet’, zɣwa ‘sea’