You might want to use a figure from a journal, book, web page, or another student's thesis or dissertation in your written work. All of this material is protected by US Copyright Law and needs to be used appropriately in order to avoid copyright infringement.
When you publish a journal article, for example, the authors (or sometimes just your advisor) sign a copyright transfer agreement. Since the authors have created the work, they own the copyright to it. By signing this agreement, the authors give the publisher permission to print the work in their journal. This agreement usually transfers the copyright from the authors to the publisher.
This information will assist you in writing a thesis or dissertation.