® is the registered trademark symbol, which is printed
in conjunction with a trademark (such as a brand name, logo or
slogan), when said trademark has been registered with a central
authority. Example: ""John put a bottle of Coca-Cola® into
the fridge." Apparently this is done in order to show that the
trademark in question is protected by law, so don't mess
with it!
Compare with ™, which is a somewhat weaker trademark protection,
whose authority originates from the holder of the trademark
itself.
What if I could successfully register ® as a trademark?
Anyone who used ® would have to put a little superscript
® after it, thus: ®®. But
that little ® symbol would in turn require to be marked
properly as a registered trademark. Since no-one can print an
infinite succession of infinitesimal symbols, everyone who used the
® symbol in print would infringe on my trademark! This
could have either of these outcomes (or both):
- Everyone would stop sprinkling their text with those annoying
® symbols.
- I could sue everyone, and become very, very rich.