| Acronym | Definition |
|---|
| HDRO➣Herr Der Ringe Online (German: Lord of the Rings Online) |
| HDRO➣Human Development Report Office (UN) |
| HDRO➣High Desert River Outfitters (rafting; Oregon) |
| HDRO➣Higher Degree Research Office (Macquarie University; North Ryde, New South Wales, Australia) |
| HDRO➣Humanitarian Disaster Relief Operations |
| HDRO➣Hook Data Readout |