The Tocharian A word trit
Word trit
Meaning third
See also Tocharian B: trite ‘third’
Proto-Indo-European: *triyós ‘third’
Avestan: θritiia- ‘third’

Other words that might be of interest
okät ‘eight’, oktuk ‘eighty’, tre ‘three’, pänt ‘fifth’, päñ ‘five’