A type of transportation device
A transportation device was any type of technology that was capable of transporting people or things to another location.
In the case of devices capable of teleportation, such a transportation device could beam a person to another location seemingly instantaneously; whereas a transportation device such as a vehicle, was often capable of driving on the ground, spaceflight or other types of travel.
In 2267, when Apollo wasn't allowing Captain James T. Kirk and his landing party to beam back to their ship, he told them "your transportation device no longer functions." (TOS: "Who Mourns for Adonais?")
In 2371, Ensign Harry Kim referred to a spatial trajector as a transportation device. He described it as "extremely sophisticated. It operates on the principal of folding space." (VOY: "Prime Factors")
That same year, Captain Kathryn Janeway speculated that a photonic lattice that the crew of the USS Voyager encountered was some type of transportation device for photonic lifeforms. She assumed it was their equivalent of a ship. (VOY: "Heroes and Demons")