[ trey-ler ] show ipa. See synonyms for trailer on Thesaurus. noun. a large van or wagon drawn by an automobile, truck, or tractor, used especially in hauling freight by road.: Compare full trailer, semitrailer. Also called travel trailer.

The short films came to be known as trailers because the projectionists originally tended to add them to the end of the reels of the B-movie in a show. Thus they trailed after the supporting movie but came before the main feature.