OA
Abbreviation with 3 meanings
| Stands for | Osteoarthritis |
|---|---|
| Meanings | 3 |
| Categories | Medical, Law & Legal, Education & Academia |
OA has three meanings. The most common are Osteoarthritis (musculoskeletal & rheumatology) and Office action (intellectual property); it can also stand for Open access.
Meanings of OA at a glance
| # | OA stands for | Context |
|---|---|---|
| 1 | Osteoarthritis | Medical › Musculoskeletal & Rheumatology |
| 2 | Office action | Law & Legal › Intellectual Property |
| 3 | Open access | Education & Academia › Academic |
1. Osteoarthritis
Medical · Musculoskeletal & Rheumatology Abbreviations
The most common form of arthritis, a whole-joint disease in which cartilage breaks down and bone, ligaments and joint lining remodel, causing pain, stiffness and reduced function. It most often affects the knees, hips, hands and spine and becomes more common with age, obesity and prior joint injury.
Example: Bilateral knee OA, Kellgren-Lawrence grade 3; continue topical diclofenac, PT, and discuss steroid injection.
Pronounced as letters. About 33 million US adults have OA, and it is a leading cause of disability worldwide. Morning stiffness typically lasts less than 30 minutes, unlike the prolonged stiffness of rheumatoid arthritis. Hand involvement produces bony Heberden nodes at the DIP joints and Bouchard nodes at the PIP joints. X-ray severity is graded with the Kellgren-Lawrence scale (0–4), published in 1957, though symptoms often correlate poorly with images. Exercise and weight loss are first-line treatments, and joint replacement is reserved for end-stage disease. Older synonyms include degenerative joint disease (DJD); "wear and tear arthritis" is now considered an oversimplification.
2. Office action
Law & Legal · Intellectual Property Abbreviations
Official letter from a patent examiner or trademark examining attorney explaining why an application cannot yet be allowed, such as rejections over prior art or formal objections. The applicant must respond by a deadline or the application is abandoned.
Example: We received a non-final OA rejecting claims 1 to 15 as obvious over two prior patents.
In US patent practice a non-final action is usually followed by a final one if issues remain; responses are generally due in three months, extendable to six for a fee. Trademark office actions generally require a response within three months, with one optional three-month extension. Restriction requirements are a common type of patent office action.
3. Open access
Education & Academia · Academic Abbreviations
Publishing model in which research articles are freely available online to anyone, rather than behind journal subscriptions. "Gold" OA publishes openly in journals, often funded by author fees, while "green" OA deposits accepted manuscripts in repositories.
Example: The funder requires all papers to be published OA with a CC BY license.
The 2002 Budapest Open Access Initiative helped define the movement. A 2022 White House memo directed US agencies to make federally funded publications freely available without embargo, and the NIH applied its version on July 1, 2025. Europe's Plan S coalition imposes similar requirements on its grantees.
Related abbreviations
More musculoskeletal & rheumatology abbreviations
- MSU – Monosodium urate
- MTSS – Medial tibial stress syndrome
- MUA – Manipulation under anesthesia
- NOF – Neck of femur (fracture)
- OCD – Osteochondritis dissecans
- OI – Osteogenesis imperfecta
- ORIF – Open reduction and internal fixation
- PFPS – Patellofemoral pain syndrome
See all 71 musculoskeletal & rheumatology abbreviations →
More intellectual property abbreviations
- IPR – Intellectual property rights
- ITU – Intent-to-use application
- MPEP – Manual of Patent Examining Procedure
- NPE – Non-practicing entity
- ODP – Obviousness-type double patenting
- PCT – Patent Cooperation Treaty
- PGR – Post-grant review
- PHOSITA – Person having ordinary skill in the art
See all 50 intellectual property abbreviations →
This entry is for general education and is not medical or legal advice. Abbreviation use varies between institutions; always confirm in context.