The Proto-Kartvelian word arwa-
Word arwa-
Meaning eight

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

Other words that might be of interest
c₁x(a)r- ‘nine’, eks1w- ‘six’, jor ‘two’, otxo- ‘four’, sam ‘three’, sam- ‘three’, šwid- ‘seven’, xut ‘five’