| Acronym | Definition |
|---|
| HSAO➣Hoger Sociaal Agogisch Onderwijs (Dutch: Higher Socio-Agogic Education) |
| HSAO➣Health and Safety Awareness Officer (UK) |
| HSAO➣Hunter Sailing Association of Oregon |
| HSAO➣Harvard Society for the Advancement of Orthodontics |
| HSAO➣Houston South Area Office (Houston, TX) |