A teamster, in modern American English, is a truck driver, or a member of the International Brotherhood of Teamsters, a labor union in the United States and Canada.
Originally, the term "teamster" referred to a person who drove a team of draft animals, usually a wagon drawn by oxen, horses, or mules. This term was common by the time of the Mexican–American War (1848) and the Indian Wars throughout the 19th and early 20th centuries on the American frontier.
In other places, a teamster was known as a carter, referring to the bullock cart.
Another name for the occupation was bullwhacker, related to driving oxen. A teamster might also drive pack animals, such as a muletrain, in which case he was also known as a muleteer or muleskinner. Today this person may be called an outfitter or packer. In Australian English, a teamster was also known as a bullocker or bullocky.