The Latin word trēs
Word trēs
Meaning three
See also Proto-Indo-European: *tréies (m), trisóres (f), treih₂ (n) tri- [prefix] ‘three’

Other words that might be of interest
omnēs ‘all’, multī ‘many’, ūnus ‘one’, duō ‘two’, quattuor ‘four’, quīnque ‘five’, cunctus ‘all, all collectively, the whole’