A wagon was a type of four-wheeled land vehicle pulled by animals.
During his first visit to Organia in 2267, James T. Kirk saw what looked like oxen pulling a wagon. (TOS novelization: Errand of Mercy)
A horse-drawn wagon was present in the O.K. Corral of the Melkots' recreation of Tombstone, Arizona in 2268. (TOS novelization: The Last Gunfight)
James T. Kirk reflected that the UNSS Lewis and Clark was a covered wagon compared to the USS Enterprise. (TOS novel: The Rings of Time)
The team pennant of the Pike City Pioneers featured a wagon. (DS9 episodes: "The Way of the Warrior", "Starship Down", ST reference: Star Trek Fact Files, ST novel: The Needs of the Many)