Answer: In order for material to be copyrightable, it must be original and must be in a fixed medium.

Only material that originated with the author can support a copyright. Items from the public domain which appear in a work, as well as work borrowed from others, cannot be the subject of an infringement claim. Also, certain stock material might not be copyrightable, such as footage that indicates a location like the standard shots of San Francisco in Star Trek IV: The Voyage Home. Also exempted are stock characters like the noisy punk rocker who gets the Vulcan death grip in Star Trek IV.

The requirement that works be in a fixed medium leaves out certain forms of expression, most notably choreography and oral performances such as speeches. For instance, if I perform a Klingon death wail in a local park, my performance is not copyrightable. However, if I film the performance, then the film is copyrightable.

Single words and short phrases are generally not protected by copyright, even when the name has been "coined" or newly-created by the mark owner. Logos that include original design elements can be protected under copyright or under trademark. Otherwise, words, phrases and titles may be protected only by trademark, however.