trailer

Etymology

From trail + -er. The film sense derives from the fact that previews were formerly shown after the main feature, rather than before as is usual today.

noun

1. Someone who or something that trails.
   There were vehicles following me, of course, but was any of them trailing me? […] Without any warning, and without signalling with the trafficator, I took a sudden right turn, hoping to shake off my trailer. 2014, Chris Ekpekurede, Laughing Over Serious Matters: Stories to Make You Laugh and Reflect
2. Part of an object which extends some distance beyond the main body of the object.
   the trailer of a plant
3. An unpowered wheeled vehicle (not a caravan or camper) that is towed behind another, and used to carry equipment, etc, that cannot be carried in the leading vehicle.
   At the end of the day, we put the snowmobiles back on the trailer.
   My trailer is a Highlander T-14 8G, one of the smallest trailers. I normally use it for carrying a pair of Sunfish sailboats that are much lighter than its 800-pound weight limit. 1980 April, Greg Stone, “Utility hauling? Do it with your boat trailer”, in Popular Science, page 104
   Or you can slide the trailer′s tandem forward toward the tractor. This changes the kingpin weight because you changed the “A” dimension of the trailer along with its wheel-base. 2004, Mike Byrnes & Associates, Bumper to Bumper: The Complete Guide to Tractor-Trailer Operations, page 310
   There is also a strong preference to avoid the cave effect associated with the front of most horse trailers and a strong desire to face the large opening between the top of the rear doors and the roof of the trailer. 2009, Norman Edward Robinson, Kim A. Sprayberry, Current Therapy in Equine Medicine, page 122
4. (US) A furnished vehicle towed behind another, and used as a dwelling when stationary; a caravan; a camper.
   We drove our trailer to Yellowstone Park.
5. (US) A prefabricated home that could be towed to a new destination but is typically permanently left in an area designated for such homes.
   The young couple′s first home was in a trailer.
6. (chiefly US, media) A preview of a film, video game or TV show.
   The trailer for that movie makes it seem like it would be fun.
7. A short blank segment of film at the end of a reel, for convenient insertion of the film in a projector.
8. (computing) The final record of a list of data items, often identified by a key field with an otherwise invalid value that sorts last alphabetically (e.g., “ZZZZZ”) or numerically (“99999”); especially common in the context of punched cards, where the final card is called a trailer card.
   The linked list terminates with a trailer record.
9. (networking) The last part of a packet, often containing a check sequence.
   The encapsulation layer adds an eight-byte header and a two-byte trailer to each packet.

verb

1. To load on a trailer or to transport by trailer.
   The engine wouldn't run any more so we had to trailer my old car to the wrecking yard.