trailern. One who, or that which, trails.()n.1. a wheeled vehicle without a motor, designed to be drawn by a motor vehicle in front of it;()2. (Movies) A short blank segment of movie film attached to the end; -- used for convenient insertion of the film in a projector.()3. (Movies) A short film consisting primarily of one or more short portions of a film, used in promotions or advertisements shortly before initial release of a film.()4. A part of an object which extends some distance beyond the main body of the object; as, the trailer of a plant.()trailer park. An area equipped to accommodate trailers{2}, often with outlets supplying electrical power and water. Called also trailer camp, trailer court.()