WordDictionary

Noun:

• computing A usually invalid value used to signal the end of a list of data, often sorting last alphabetically ("ZZZZZ") or numerically ("99999") among all possible valid values; especially common in punched cards, where the final card is called a ''trailer card''.
• Australia|NZ|US A small vehicle, usually open-topped, towed behind another, and used for carrying equipment, etc, that cannot be carried in the leading vehicle.
• British Any vehicle designed to be towed, with the exception of a caravan.
• mainly US|media A preview of a film or TV show.
• US A furnished vehicle towed behind another, and used as a dwelling when stationary.
• US A prefabricated home that could be towed to a new destination, but typically is permanently left in an area designated for such homes.
• networking the last part of a packet, often containing a check sequence
• someone or something that trails

Verb:

• To load on a trailer or to transport by trailer.