"A Registered Investment Adviser (RIA) is an investment adviser (IA) registered with the Securities and Exchange Commission or a state's securities agency." [0]
"A Registered Investment Advisor is defined by The Investment Advisers Act of 1940 as a "person or firm that, for compensation, is engaged in the act of providing advice, making recommendations, issuing reports or furnishing analyses on securities, either directly or through publications." An investment advisor has a fiduciary duty to his or her clients, which means that he or she has a fundamental obligation to provide suitable investment advice and always act in the clients' best interests." [1]
"A Registered Investment Advisor is defined by The Investment Advisers Act of 1940 as a "person or firm that, for compensation, is engaged in the act of providing advice, making recommendations, issuing reports or furnishing analyses on securities, either directly or through publications." An investment advisor has a fiduciary duty to his or her clients, which means that he or she has a fundamental obligation to provide suitable investment advice and always act in the clients' best interests." [1]
[0] https://en.wikipedia.org/wiki/Registered_Investment_Advisor
[1] http://www.investopedia.com/terms/r/ria.asp