A trailer is a container on wheels that is pulled by a vehicle and equipped to hold large or heavy items. It can also be used as a place to sleep or work in when traveling. Trailers are usually made to withstand the elements and are often used as camping and hunting vehicles.

The word “trailer” is a portmanteau of the words “towed” and “cargo.” The term has been in use since 1922 and has been derived from an earlier naming convention for railroad freight transport cars, which were sometimes known as trailers. These days, the word trailer is used for any type of hauling vehicle. A trailer can be used for many types of cargo, including furniture, machinery, livestock, and other bulky or unwieldy items.

Although trailers are typically associated with film, they can be created for any type of media: television shows, video games, books, and theatrical events or concerts. A successful trailer tells a story that draws in the audience and makes them want to see the movie or product in question. The most effective trailers are able to convey the film’s main theme and characters in a brief and compelling manner.

Most modern-day trailers are arranged in a three act structure, with the beginning introducing the main character and setting, the middle heightening conflict, and the end featuring a climax. The trailer’s music and sound effects play a major role in establishing its tone and mood. Music with a driving beat, for example, can add energy while music with light violins can create tension. Sound effects can also provide important information to the audience, such as the distant sounds of battle for a war movie or ambient futuristic noises for science fiction.

One of the most common and effective strategies for a trailer is to include a cold open, which introduces the main character and scene with an exciting, dramatic, or humorous action sequence. The opening scene of a trailer is meant to grab the viewer’s attention, and it is generally less than two minutes long. This is a common practice because viewers are believed to have shorter attention spans than in the past and must compete with an ever-increasing stream of entertainment, both online and on their televisions and mobile devices.

Another popular strategy is to highlight the film’s cast run, a list of all the actors who appear in the film along with any notable directors, producers, or writers. The cast run is typically placed near the end of a trailer to draw in audiences who may be interested in seeing these celebrities in their latest projects.

The art of creating a great trailer has become an increasingly specialized field, with companies and editors dedicated to the task and vast websites maintained to catalog and critique them. Yet, despite the immense effort and expense involved, it is not always clear whether or not these trailers will increase ticket sales. Perhaps they are being viewed by the wrong audiences, or perhaps they are being made in a language that is too complicated for them to understand.