Full context:   An ancient Roman car or chariot pulled by four horses abreast together with the horses pulling it was called a Quadriga, from the Latin quadriugi (of a team of four). The term sometimes meant instead the four horses without the chariot or the chariot alone. A three-horse chariot, or the three-horse team pulling it, was a triga, from triugi (of a team of three). A two-horse chariot, or the two-horse team pulling it, was a biga, from biugi.