Shredded wheat, cellophane, thermos, yo-yo, cola - and now Monopoly. What do they all have in common? They all have had their trademarks invalidated because courts have said their names fell into common use.
The US Supreme Court's stripping of Parker Brothers' 47-year-old monopoly on Monopoly this week has triggered a wave of negative reaction from product manufacturers across the United States who anxiously ask the question: Who's next?
''It could happen to you! The ramifications for all trademark holders are grave. Very few trademarks could withstand this particular test - unless the trademark is identical with the corporation's name.''
This is the assessment of Robin Rolfe, executive director of the United States Trademark Association (USTA).
In letting stand a lower court ruling by refusing to hear Parker Brothers' appeal, the high court paved the way for a competitor's game, Anti-Monopoly.
A trademark protects a business from having its name or symbol of its products or services unjustly used by a competitor.
Further legal action by General Mills Inc. (of which Parker Brothers is a division) is not seen as likely now.
But a host of interested parties - including Procter & Gamble, the Grocery Manufacturers of America, the US Chamber of Commerce, and the National Association of Manufacturers - all of whom filed friend-of-the-court briefs on behalf of Parker Brothers - indicate they will look closely for cases that might modify the present ruling or even bring the matter back to the Supreme Court in new form.
Further, some legal experts say this action could put pressure on Congress to amend the Lanham Act, the congressional legislation of 1946 which authorizes current federal trademark law.
Boston attorney Warren Thomson, a trademark research specialist, says, ''It's bad law which I think will be attacked on the legislative side.''
What Mr. Thomson, product manufacturers, and others challenge is the rationale of the US court of appeals in Chicago. In effect, it is this:
Monopoly has become a generic term and cannot be controlled by a single manufacturer. This decision was based in part on a 1938 case involving shredded wheat, where the US Supreme Court said the breakfast-food name had become so generic that it could no longer be limited to use by a single cereal maker.
The appellate court panel also based its ruling on a marketing survey that showed that most prospective purchasers of Monopoly were prodded to buy it because of their interest in the game. Consumers weren't really interested in who the manufacturer might be - and even had a difficult time identifying Parker Brothers, the survey held.
''When a trademark primarily denotes a product, not a product's producer, the trademark is lost,'' the court said.
Ms. Rolfe finds this faulty reasoning. ''What it seems to say,'' the USTA official insists, ''is that brand identification isn't enough unless a consumer identifies the product with a specific manufacturer.
''We believe that the trademark in and of itself functions as an identification of the service or the origin of the goods,'' she explains.
The Monopoly case has been bouncing around the courts for a decade. The legal dispute began when Parker Brothers in 1973 challenged, on the basis of trademark infringement, a professor of economics at San Francisco State University, Ralph Anspach, who was marketing his own game, Anti-Monopoly.
Mr. Anspach countered with a suit to have Monopoly's trademark declared invalid. Two district court rulings in California found in favor of Parker Brothers.
The appeals court did agree, however, with the district court that Monopoly wasn't a generic term when Parker Brothers first acquired it in 1935. But it still concluded: ''If those who might purchase the thing know it by particular name, then to forbid the use of that name by potential producers will erect unwarranted barriers of competition.
''Trademarks . . . are not properly used as patent substitutes to further or perpetuate product monopolies,'' the appeals court concluded.
Parker Brothers claims the court misread other leading opinions in which well-known trademarks - including the names ''aspirin,'' ''cellophane'' and ''thermos'' - were invalidated for being generic. In contrast to these brands, the toymaker insisted, there is only one producer of the Monopoly game.