Let’s say I want to create a modern fancy designer dog toy product called simply ‘boule’ (French for ball). I have registered my trademark on the U.S. Patent and Trademark Office’s Web site. Now what if I later realize that another company has previously registered their own dog toy product called “le boule” which means ‘the ball’ in French. Does the fact that my trademark is slightly different (but confusingly similar) matter? Could I easily be sued/have no legal argument if I trademark a name for a product that is similar (but not identical) to something that was registered and sold significantly earlier than my product?
I will assume IANAL applies unless otherwise stated.
If the products are the same, and the two trademarks are similar enough to be confused, then you’re in trouble. You probably couldn’t get the trademark registered under the conditions in your post, so it’s a moot point.
The company owning “le boule” would sue to deny you the trademark if it were ever issued, and they’d have a strong case.
Now, if they did a dog toy and you used it for a rhoomba-like vacuum cleaner, there would be no confusion and the two of you could probably both use it.
First, kudos for specifying that you are asking about the situation in the USA. Not many posters bother with that important piece of information.
As RealityChuck alludes to, If your product is a ball, don’t call it “ball” in English or in any of the major languages on earth. Doing so may make it difficult to get it registered as a trademark. After all, you wouldn’t let someone trademark the word MILK for selling milk, would you? If you did, that would mean no one else who sells milk could use the word milk in their advertising.
If the goods sold and the trademarks are similar enough to cause your average droopy-eyed consumer to be confused as to which is which, or to mistake yours for the other brand, or vice versa, then there is probably enough grounds for the prior owner/registrant to sue for infringement.