A wagon was a land vehicle with four wheels that was often pulled by horses or other large quadruped animals. This type of vehicle was especially common during the Ancient West.
Around 1930, the Victor Ice Company made deliveries with a horse drawn wagon. (TOS: "The City on the Edge of Forever")
In 2285, when Sulu told the USS Enterprise crew that the USS Excelsior was supposed to have transwarp drive, Scotty sarcastically remarked, "And if my grandmother had wheels, she'd be a wagon." (Star Trek III: The Search for Spock)
The team pennant of the Pike City Pioneers featured a wagon. (DS9: "The Way of the Warrior", "Starship Down")