AAR

noun2

1. •
   after-action report; after-action review.
2. •
   Aircraft accident report.

prepositional phrase2

1. •
   against all risks.
2. •
   At any rate.

noun1

1. •
   A river in Switzerland, flowing 292 km from the glaciers of the Bernese Alps into the Rhine at Koblenz, on the Swiss–German border.