The term PT. OF AARP is an acronym for four words: Retired (RETD), Retiree (RET), American (AMER), and Association (ASSN). Together, these words form the phrase 'Retired Retiree of the American Association, ' which refers to a person who is retired and a member of the American Association of Retired Persons (AARP). AARP is a nonprofit organization that provides resources and advocacy for people over the age of 50.