Air carrier Captain reported confusion with ATC use of terminology of the SDF airport name.

Narrative

Louisville air traffic controllers continue to use 'Standiford' when referencing Louisville Muhammad Ali International Airport.The name changed in January of 2019 - over seven (7) years ago.Continuing to use 'Standiford' creates potential confusion that can lead to safety issues. It also creates problems for legality of clearances that are issued.As a point of reference; our company is the one of the airlines that operates frequently into and out of Louisville Muhammad Ali International Airport. Many company pilots were hired after the name officially changed. Many pilots do not know the airport's history. None of our pilots have Jeppesen charts for Standiford.During our arrival into Louisville Muhammad Ali International Airport; the approach controller repeatedly issued visual approach clearances that were confusing at best and illegal. The exchanges went as follows:Louisville Approach: 'Aircraft X; Standiford is at 2 o'clock.'Aircraft X: 'Airport in sight; Aircraft X.'Louisville Approach: 'Aircraft X; cleared visual approach 3-5 Left.'I know that this may be a habit on the part of the controller; but it is not that difficult to state; 'Muhammad Ali is at 2 o'clock' or 'Louisville International is at 2 o'clock.' This would eliminate ambiguity/confusion and put an end to the dubious legality of a clearance to an airport that no longer exists.Similarly; I have never heard controllers refer to GEG as 'Geiger'; to MSY as 'Moisant'; to ORD as 'Orchard'; or to MCI as 'Mid-Continent International.'Recently; I have heard Louisville tower controllers communicating with General Aviation aircraft or with helicopters operating around Louisville Muhammad Ali International Airport. I have heard them issue directives along the lines of 'Remain west of Standiford.'For pilots trying to maintain situational awareness to other aircraft who are unfamiliar with the outdated name; this creates a safety issue.