This definition appears very rarely
See other definitions of AD
Samples in periodicals archive:
GSA establishes the maximum CONUS (Continental United States) Per Diem rates for federal travel customers.
Please check that a per diem is available for the city you are visiting before you undertake your trip. The cities are determined by HMRC and are not at the...
Per Diem Rates. Allowances for lodging, meal and incidental costs while on official government travel. Get Started