There are multiple definitions:

1. oculus sinister(Latin)

   • left eye (English)
   • LE, OU, OD
   • Ophthalmology

2. overshoot(English)

   • ap
   • Electrophysiology

3. operating system(English)

   • Microsoft, Linux, GUI
   • Computing (biomedical)

4. opening snap(English)

   • DFP, MS, MVA
   • Cardiology

5. oxidative stress(English)

   • results from imbalance of prooxidant and antioxidant forces, and informs how ASCVD risk factors relate to each other
   • LPO, MOE, TRPV, ASCVD, eNOS, HTN, RBC, ROS, SMC
   • Atherosclerosis /atherogenic
   • https://doi.org…795468231170779

6. overall survival(English)

   • MACE, PFS, DFS, RFS, LODDS, TNM, pTNM, ARE, BM, BRAF, BRAFi, DS-GPA, GKRS, KPS, MEK, mOS, RN, SRN, SRS, WBRT
   • Clinical trials, Quality and outcomes, Epidemiology
   • http://www.jcan…rg/v10p3717.htm
   • https://doi.org…can.2020.12.019
   • https://doi.org…/2016.2.JNS1633

7. osteosarcoma(English)

   • most commonly found in the posterior elements of the sacral and thoracic spine. Paget's disease is a known risk factor, but less than 1% of these patients will develop malignant transformation. The prognosis of patients with spinal osteosarcomas continues to be poor. Osteosarcomas are generally radioresistant lesions, and traditional radiotherapy has limited benefit in the treatment of this pathology. Adjuvant chemotherapy plays a role in the treatment of patients with spinal osteosarcoma
   • Oncology
   • https://doi.org…52910-7.00016-7

8. olfactory score(English)

   • ACE2, COVID-19, EBG, OB, OC, OE, OF, OR, OS, OSN, OT, SUS
   • Olfactory system, Scoring systems/scales
   • https://doi.org…455613211048998

9. outer segment(English)

   • refers to retinal architecture
   • IS, L-ORD, ONL, OPL, Wtrdt
   • Ophthalmology, Genetics, Molecular biology
   • http://www.molv…/molvis/v21/273

10. overall satisfaction(English)

    • refers to sexual dysfunction and enlargement of seminal vesicles in sexually active men who were treated by α1-blockers for benign prostatic hyperplasia
    • IIEF, LUTS, QOL
    • Prostate, Sexuality, Urology
    • https://doi.org…ogy.2017.08.025

11. opportunistic salpingectomy(English)

    • this strategy emerged as an approach to reduce ovarian-cancer risk as evidence suggested that high-grade serous ovarian cancers originate in the fallopian tubes
    • BS, BTL
    • Ovary and uterus, Surgery, Oncology
    • https://doi.org…07.CAPR-21-0121

12. Olmsted syndrome(English)

    • a rare hereditary disorder classically marked by bilateral mutilating palmoplantar keratoderma and periorificial keratotic plaques. It has an early onset in the neonatal period or during childhood
    • IFAP, MBTPS2, PPK, TRPV3
    • Dermatology, Neonatal situation, Pediatrics, Genetics
    • https://doi.org…55/2020/8024981

13. oral solution(English)

    • in dehydrated children presenting to the emergency department with acute gastroenteritis
    • ED, ODT, AGE
    • Gastroenterology, Emergency medicine, Pediatrics
    • https://doi.org…med.2016.06.051

14. observation status(English)

    • refers to patients (0-18 years) transferred to pediatric observation beds from the emergency department
    • AGE, ED
    • Emergency medicine, Pediatrics, Asthma, Gastroenterology, Triage
    • https://doi.org…106238.72265.5f

15. oral [mucosal] space/surface(English)

    • ROT, SLS
    • Dentistry, Anamnesis
    • https://doi.org…47782-6.50012-0

16. occipital sinus(English)

    • SSS, StS
    • Anatomy, Brain (dys)function
    • https://doi.org…65377-0.00007-6

17. Ohtahara syndrome(English)

    • a peculiar early onset epileptic syndrome with serious prognosis. The outline, mainly in relation to the evolution with age, and differentiation from related conditions, particularly early myoclonic encephalopathy
    • EEG, EME, SB
    • Epilepsy or syncope, Brain (dys)function, Electrophysiology
    • https://doi.org…res.2005.11.021

18. organic solvent(English)

    • BisGMA, UDMA, PENTA, HEMA, MDP
    • Dentistry, Materials science
    • https://doi.org…220345231175868