A webisode is an episode of a series that is distributed as web television. It is available as either for download or in streaming, as opposed to first airing on broadcast or cable television. The format can be used as a preview, a promotion, as part of a collection of shorts, or a commercial. A webisode may or may not have been broadcast on TV. What defines it is its online distribution on the web, or through video-sharing web sites such as Vimeo or YouTube. While there is no set standard for length, most webisodes are relatively short, ranging from 3–15 minutes in length. It is a single web episode, but collectively is part of a web series, a form called web television that characteristically features a dramatic, serial storyline, where the primary method of viewership is streaming online over the Internet. The term webisode (a portmanteau formed from the words 'web' and 'episode') was first introduced in the Merriam-Webster's Collegiate Dictionary in 2009.