To be protected by copyright, original works must be fixed in a tangible form of expression. For example, improvisational performances or choreographic works that have not been notated or recorded are not protected. Titles, names, short phrases, slogans, familiar symbols and designs are also not protected under Copyright Law, but they may be protected under Trademark Law. Similarly procedures, processes, and systems, although not protected under copyright, may be protected under Patent Law.

Categories of unprotected works include:

• Facts
• Works already in the public domain
• Federal documents
• Ideas, concepts, principles
• Works containing no original authorship (e.g., calendars, height and weight charts, and rulers)
• Common property (e.g., Wikipedia)