a short publicity film, preview, or advertisement composed of short excerpts and scenes from a forthcoming film or coming attraction, usually two-three minutes in length; often presented at the showing of another film. Historically, these advertisements were placed at the end of a newsreel or supporting feature and so "trailed" them, hence the name; also commonly known as preview(s); also, another name for the tail - a length of blank leader (strip of film) at the end of a reel; a teaser is basically a very short trailer (of 15-30 seconds in length) that only provides a few hints about the film (a Web address, a few bars of music, a quick sequence of images, specially-shot footage, etc.).