The spokeswoman said: "While the duke and duchess are focused on plans to establish a new non-profit organisation, given the specific UK government rules surrounding use of the word Royal, it has been therefore agreed that their non-profit organisation, when it is announced this spring, will not be named Sussex Royal Foundation.
The couple said on Wednesday that their lives as working royals will end on March 31 when they stop representing the Queen and become financially independent.
Harry and Meghan will embark on a new chapter in North America, but sources have stressed they "will be in the United Kingdom regularly" and retain the same charitable goals supporting causes from the Commonwealth to mental health.
Last official appearance
The duke and duchess will attend the Commonwealth Day service at Westminster Abbey on March 9, likely to be their last official appearance as working members of the monarchy, with the Queen and other senior royals.
The event is normally attended by the Prince of Wales, Duchess of Cornwall and Duke and Duchess of Cambridge and is a major engagement in the Queen's calendar.
Harry and Meghan set up the website of sussexroyal.com which was registered in March 2019 and detailed the couple's plans for their roles in the monarchy and relationship with the media.
The @SussexRoyal Instagram account, started in April 2019, has since amassed 11.2 million followers.