"Daniel Snyder may be the last person in the world to realize this, but it's just a matter of time until he is forced to do the right thing and change the name," said Reid, who has said previously he will not attend Redskins home games until the team changes its name.
The new case was launched in 2006 by a younger group of Native Americans and was heard by the board in March 2013.
The group argued that the Redskins should lose their federal trademark protection based on a law that prohibits registered names that are disparaging, scandalous, contemptuous or disreputable.
"The U.S. Patent Office has now restated the obvious truth that Native Americans, civil rights leaders, athletes, religious groups, state legislative bodies, Members of Congress and the president have all echoed: taxpayer resources cannot be used to help private companies profit off the promotion of dictionary defined racial slurs," said Oneida Indian Nation representative Ray Halbritter and National Congress of American Indians executive director Jackie Pata in a joint statement.
"If the most basic sense of morality, decency and civility has not yet convinced the Washington team and the NFL to stop using this hateful slur, then hopefully today's patent ruling will, if only because it imperils the ability of the team's billionaire owner to keep profiting off the denigration and dehumanization of Native Americans.
Without protection, any fan can produce and sell Washington Redskins gear without having to pay the league or the team for royalties and wouldn't be in violation of any law for doing so. NFL teams split merchandise royalties 31 ways -- the Dallas Cowboys have their own deal -- so league owners could see losing the trademark rights as a major negative.
"This is not a death blow, but it's a good jab," said Frank Vuono, who formerly headed up the NFL's retail operations before starting his own firm, 16W Sports Marketing.
Vuono said that not only could merchandise be compromised, but if the Redskins someday lose their rights to the trademarks, non-sponsors could try to use the marks to associate with the team without affiliation. That, Vuono said, would devalue the proposition of being an official sponsor.
The Redskins are an integral part of league sales. From April 1, 2012, to March 2013, the league said more jerseys of Redskins quarterback Robert Griffin III were sold than of any other player in a single year in NFL history.
"In a business like professional football, there is a huge amount of revenue in merchandising," Christine Farley, a law professor at American University who specializes in trademarks, told ABC News. "If pro football loses the ability to monopolize that market, that may convince them to change their name."
If the Redskins lose the rights to their trademarks, the question will be whether state and common laws would allow them to retain their exclusivity of use.
"The law is really unclear on this," said Sonia Katyal, the Joseph M. McLaughlin Professor of Law at Fordham who specializes in intellectual property. "We haven't really had something like this where you have a team and so many other interested parties involved, so we're treading new ground."
Suzan Shown Harjo, one of the plaintiffs who testified at last year's hearing, said she was "thrilled and delighted'' with the decision.