“Ar” means a city

Ar: or Ar of Moab, one of the chief places of Moab. (Numbers 21:28; Isaiah 15:1) In later times the place known as Areopolis and Rabbath-Moab. The site still called Rabba . It lies about halfway between Kerak and the Wady Mojeb , 10 or 11 miles from each, the Roman road passing through it.