| OP | occipitoparietal; occipitoposterior; occiput posterior; octapeptide; olfactory peduncle; opening pre... |
|---|---|
| ORS | olfactory reference syndrome; oral rehydration solution; oral surgery, oral surgeon; Orthopaedic Res... |
| OT | objective test; oblique talus; occlusion time; occupational therapist, occupational therapy; ocular ... |
| OTU | olfactory tubercle; operational taxonomic unit |