triumvirate (n.) Look up triumvirate at Dictionary.com
1580s, from Latin triumviratus, from triumvir (see triumvir).
troika (n.) Look up troika at Dictionary.com
1842, "carriage drawn by three horses abreast," from Russian troika "three-horse team, any group of three," from collective numeral troje "group of three" (from PIE *tro-yo-, suffixed form of *trei-, see three) + diminutive suffix -ka. Sense of "any group of three administrators, triumvirate" is first recorded 1945.