R is the abbreviation of REGISTER, which means registered trademark when used in trademarks.
circled r is the mark of "registered trademark", which means that the trademark has been applied for registration in the State Trademark Office and passed the examination by the Trademark Office, and has become a registered trademark.
R trademark has the characteristics of exclusiveness, exclusivity and uniqueness, which belongs to the owner of the registered trademark and is protected by law. No enterprise or individual may use it without the permission or authorization of the owner of the registered trademark, otherwise it will bear the tort liability.