R81
R81 denotes:
- Mr. Ms. Karel Doorman (R81) , a Dutch ship
- HMS Zebra (R81) , a British ship
- a bus from Magirus-Deutz, see Magirus-Deutz #Short bus L80 and club buses R80 and R81
- a regional train line in the greater Nuremberg area, see R-Bahn Nuremberg
- " Glucosuria " (ICD-10 Diagnostic Code), one of the abnormal urine test results without a diagnosis