Mr.
Abbreviation with 8 meanings
| Stands for | Mister |
|---|---|
| Meanings | 8 |
| Categories | Writing & Everyday, Medical, Technology & Computing, Business & Finance, Geography & Places |
| Also written | MR |
Mr. has eight meanings. The most common are Mister (title and honorific) and Mitral regurgitation (cardiology); it can also stand for Mixed reality, Magnetic resonance, Merge request, Marginal revenue and Modified release, plus 1 more listed below.
Meanings of Mr. at a glance
| # | Mr. stands for | Context |
|---|---|---|
| 1 | Mister | Writing & Everyday › Title and Honorific |
| 2 | Mitral regurgitation | Medical › Cardiology |
| 3 | Mixed reality | Technology & Computing › Consumer Electronics |
| 4 | Magnetic resonance | Medical › Medical Imaging |
| 5 | Merge request | Technology & Computing › Programming |
| 6 | Marginal revenue | Business & Finance › Economics |
| 7 | Modified release | Medical › Pharmacy |
| 8 | Mauritania | Geography & Places › Country Code |
1. Mister
Writing & Everyday · Title and Honorific Abbreviations
The standard courtesy title for a man, placed before his surname or full name regardless of marital status. It appears in correspondence, formal address, school settings, news writing and on forms.
Example: Mr. Alvarez will meet parents in the library after the assembly.
American English puts a period after Mr., while British English usually omits it (Mr) because the abbreviation ends with the last letter of the full word, a rule that also covers Mrs, Dr and St. "Mister" is rarely spelled out before a name except for effect, as in Mister Rogers. AP style drops courtesy titles in most news copy, using surnames alone on second reference. The plural is Messrs.
2. Mitral regurgitation (MR)
Medical · Cardiology Abbreviations
Backward leakage of blood through the mitral valve into the left atrium during each heartbeat, graded mild, moderate or severe by echocardiography. Primary MR comes from the valve itself, such as prolapse or a torn chord, while secondary MR results from a dilated or damaged left ventricle.
Example: Holosystolic murmur at the apex radiating to the axilla; TTE shows severe MR from a flail posterior leaflet.
Also called mitral insufficiency. Severe primary MR is usually treated surgically, and repair is preferred over replacement when feasible. Patients at high surgical risk may receive transcatheter edge-to-edge repair with devices such as MitraClip. Outside cardiology MR more often means magnetic resonance or medical record.
3. Mixed reality (MR)
Technology & Computing · Consumer Electronics Abbreviations
Technology that blends real and virtual worlds so digital objects appear anchored in the physical environment and can interact with it, typically through a headset with cameras that show the room. It sits between AR and VR.
Example: In MR mode, the virtual chessboard sits on my real coffee table and stays put as I walk around.
Paul Milgram and Fumio Kishino described the "reality-virtuality continuum" in 1994. Microsoft's HoloLens (2016) and Windows Mixed Reality headsets popularized the term; Microsoft later dropped Windows Mixed Reality, removing it from Windows 11 in 2024. Meta's Quest 3 uses color camera passthrough for MR, and Apple markets its Vision Pro as "spatial computing".
4. Magnetic resonance (MR)
Medical · Medical Imaging Abbreviations
Radiology shorthand for magnetic resonance imaging and its variants, used in orders and safety labels such as "MR enterography", "MR arthrogram", "MR safe" and "MR conditional". Radiologists often say MR rather than MRI when naming a specific technique.
Example: MR arthrogram of the right shoulder to evaluate the labrum.
Implant labeling follows the ASTM system: MR safe, MR conditional (safe only under stated scanner conditions) or MR unsafe. In cardiology MR means mitral regurgitation, and on drug labels it can mean modified release, so a body part or device next to it signals the imaging sense.
5. Merge request (MR)
Technology & Computing · Programming Abbreviations
GitLab's name for a proposal to merge code changes from one branch into another, with review, discussion and CI results attached; it is the equivalent of a GitHub pull request.
Example: The MR is approved, but the pipeline must pass before GitLab allows the merge.
GitLab argues that "merge request" describes the action more accurately, since the reviewer merges rather than pulls. Draft MRs, marked "Draft:", signal that work is not ready for final review. MR has many other meanings, from "Mister" to magnetic resonance; in GitLab contexts it always means a merge request.
6. Marginal revenue (MR)
Business & Finance · Economics Abbreviations
Additional revenue a firm earns from selling one more unit. For a competitive firm MR equals the market price, while a monopolist must cut its price to sell more, so its MR is below price.
Example: The airline's MR on the last few seats is low because it must discount them to fill the plane.
The profit-maximizing rule that MR should equal MC is a cornerstone of microeconomics. For a linear demand curve, the MR curve falls twice as steeply as demand. MR turns negative where demand is inelastic, meaning a firm could raise revenue by selling less.
7. Modified release (MR)
Medical · Pharmacy Abbreviations
British and European umbrella term for any formulation in which the rate or place of drug release differs from a conventional tablet, covering extended, prolonged and delayed release. It appears in UK drug names such as gliclazide MR and nifedipine MR.
Example: Gliclazide MR 30 mg once daily with breakfast; review HbA1c in 3 months.
The British National Formulary advises prescribing some modified-release drugs, such as nifedipine, diltiazem and theophylline, by brand name because different brands release the drug differently. In US usage "modified release" is a general category rather than a product suffix. In cardiology MR means mitral regurgitation.
8. Mauritania (MR)
Geography & Places · Country Code Abbreviations
Mauritania, capital Nouakchott, alpha-3 MRT, is mostly Sahara Desert and contains the Richat Structure, a 40-kilometre circular formation called the Eye of the Sahara. It formally abolished slavery in 1981, among the last countries to do so.
Example: Iron ore trains in MR are among the longest in the world, stretching about 2.5 kilometres.
The ouguiya, Mauritania's currency, is non-decimal, divided into five khoums. The language code mr means Marathi.
Related abbreviations
More title and honorific abbreviations
- Messrs. – Messieurs (plural of Mr.)
- Mlle. – Mademoiselle
- Mme. – Madame
- Mmes. – Mesdames (plural of Mrs. or Madame)
- Mrs. – Missus (originally Mistress)
- Ms. – Ms. (title for a woman regardless of marital status)
- Mx. – Mx. (gender-neutral courtesy title)
- OBE – Officer of the Order of the British Empire
See all 54 title and honorific abbreviations →
More cardiology abbreviations
- METs – Metabolic equivalents
- MI – Myocardial infarction
- MINOCA – Myocardial infarction with nonobstructive coronary arteries
- MPI – Myocardial perfusion imaging
- MRG – Murmurs, rubs or gallops
- MUGA – Multigated acquisition scan
- MV – Mitral valve
- MVP – Mitral valve prolapse
See all 229 cardiology abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.