At least in common usage terms, when you hear AA personnel refer to a record locator (other than reservations people talking to customers) they call it the PNR. If I ask for the PNR, I'm given the record locator number. They are used interchangeably by Airline personnel.
And it's always a 6 digit number on AA, not a 5 digit number. (technically, as stated above, it's not a number, because it consists of both number and letters.)