1. 1. A Russian carriage drawn by a team of three horses abreast.
   2. A team of three horses abreast.
2. See triumvirate (sense 4).

[Russian troĭka, from troje, group of three.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.