There are multiple definitions:

1. Operation Restore Trust(English)

   • Medicare and Medicaid
   • Health insurance

2. oral rehydration therapy(English)

   • CFTR
   • Therapeutic approaches

3. onregelmatigheidstoeslag(Dutch)

   • BAD, TOD
   • Legal issues

4. object recognition test(English)

   • to evaluate the effect of stress on short-term learning abilities; aka NOR
   • MPEP, NAM, NMDAR, PAM, PCP, ISAMM, CDPPB, NOR
   • Memory, Experimental animal, Cognitive function
   • https://doi.org…pbp.2003.09.028
   • https://doi.org/10.3791/55718

5. orthodromic reentry / reciprocating tachycardia(English)

   • AVNRT
   • Cardiology, Electrophysiology
   • https://doi.org…thm.2010.05.033

6. operating room time(English)

   • BO, CBI, COVID-19, IPU, LPA, MBI, MBI-SS, Pa-BO, Pe-BO, W-BO, OR
   • Surgery, Fatigue
   • https://doi.org…rol.2021.01.015

7. ovarian reserve test(English)

   • FSH, IVF, ICSI, OHSS
   • Ovary and uterus, Hormone
   • https://doi.org…8.CD012693.pub2