Definitions
copyright - An author's original work is under copyright protection the moment it is created and fixed in a tangible form. Registration with the U.S. Copyright Office is voluntary.
Creative Commons licenses - These licenses work within copyright law to allow authors to grant permission to everyone for the use of their work in certain ways, depending on the type of CC license chosen.
fair use - Fair use doctrine permits the unlicensed use of copyright-protected works in certain circumstances. Criticism, comment, news reporting, and scholarship are examples of activities that may qualify as fair use.
open access content / open educational resources - These resources may be shared and reused with attribution to the original author. Remixing and adapting of the material may also be allowed depending whether a Creative Commons license is used.
public domain - In general, the term of copyright is the life of the author plus 70 years after the author's death. After the term expires, the work is in the public domain unless the copyright is extended. In the U.S., a book is in the public domain if it was published before 1923.
work for hire - When the author is hired to create the work, the party that hired the individual is considered both the author and the copyright owner of the work.