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1842, "carriage drawn by three horses abreast," from Russian troika "three-horse team, any group of three," from collective numeral troe "three" + diminutive suffix -ka. Sense of "any group of three administrators, triumvirate" is first recorded 1945.
(Russian: "three"), any vehicle drawn by three horses abreast, usually a sleigh with runners but also a wheeled carriage. The three-horse team is also known as a unicorn team.