[balls187]

Specific to the US, my interpretation:

Prior to SECs recent ruling which allows companies to sell shares (aka securities) by crowd funding, companies are allowed to sell shares to Accredited Investors, the definition of which is regulated by the SEC. Further, they can also sell shares to non-accredited investors, but with added due diligence required by the company.

An individual can meet the definition of an accredited investor, without being an "Angel Investor." Angel Investor is a term for someone who is known for, as part of a financial strategy, investing their own money to startups.