This new federal definition standardizes the meaning of “gluten-free” claims across the food industry. It requires that, in order to use the term "gluten-free" on its label, a food must meet all of the requirements of the definition, including that the food must contain less than 20 parts per million of gluten. The rule also requires foods with the claims “no gluten,” “free of gluten,” and “without gluten” to meet the definition for “gluten-free.”
Click on image to read the entire ruling
For all the details and answers to questions you might have, please visit the FDA's Q&A page.
I also recommend reading Jules Shepard's blog post on this issue. She, John Forberger, and the American Celiac Disease Alliance were instrumental in getting these standards set in place. In 2011 they founded 1in133.org to spread awareness on the importance of gluten free labeling. You may have remembered the World's Tallest Gluten Free Cake they constructed to pressure law makers on finalizing gluten free labeling standards that were promised in 2007 to be done within five years. A little late, but hey, better late than never!