Cars refers to a wheeled vehicle that moves independently, with at least three wheels, powered mechanically, steered by a driver and mostly for personal transportation. It commonly describes a wheeled vehicle, drawn by a horse or other animal; a chariot, an unpowered unit in a railroad train, and an individual vehicle, powered or unpowered, in a multiple unit, which gives the term a broader and more practical sense than a single short definition would suggest. Depending on context, it can also point to a passenger-carrying unit in a subway or elevated train, whether powered or not, a rough unit of quantity approximating the amount which would fill a railroad car, and the moving, load-carrying component of an elevator or other cable-drawn transport mechanism, so the category can cover literal uses, related ideas, and more figurative extensions of the same core meaning. Taken together, these meanings present Cars as a flexible theme rather than a narrowly technical label, covering the central idea people usually mean when they use the word while still leaving room for closely related senses that appear in real language. Additional shades of meaning include the passenger-carrying portion of certain amusement park rides, such as Ferris wheels, the part of an airship, such as a balloon or dirigible, which houses the passengers and control apparatus, a sliding fitting that runs along a track, the aggregate of desirable characteristics of a car, and a floating perforated box for living fish, which reinforce how the category can stretch across adjacent but still recognizable uses of the same term.
