CIS
Abbreviation with 3 meanings
| Stands for | Clinically isolated syndrome |
|---|---|
| Meanings | 3 |
| Categories | Medical, Organizations & Companies, Units & Measurements |
| Also written | cis |
CIS has three meanings. The most common are Clinically isolated syndrome (neurology) and Commonwealth of Independent States (international organization); it can also stand for Cosine plus i sine.
Meanings of CIS at a glance
| # | CIS stands for | Context |
|---|---|---|
| 1 | Clinically isolated syndrome | Medical › Neurology |
| 2 | Commonwealth of Independent States | Organizations & Companies › International Organization |
| 3 | Cosine plus i sine | Units & Measurements › Math |
1. Clinically isolated syndrome
Medical · Neurology Abbreviations
First episode of neurological symptoms lasting at least 24 hours that is typical of demyelination, such as optic neuritis, a brainstem syndrome or partial myelitis, in a person not yet meeting criteria for multiple sclerosis. MRI findings largely determine the chance of later MS.
Example: CIS with left optic neuritis; three typical periventricular lesions, high risk of conversion to MS.
Patients whose brain MRI already shows typical lesions have a much higher chance of a second attack than those with a normal scan. Under the 2017 McDonald criteria, CSF oligoclonal bands or new lesions on follow-up can allow an MS diagnosis after a single episode. Early treatment of high-risk CIS delays a second attack.
2. Commonwealth of Independent States
Organizations & Companies · International Organization Abbreviations
Loose regional organization of former Soviet republics formed in December 1991 as the Soviet Union dissolved, which coordinates on trade, security and other matters. Its executive body is based in Minsk, Belarus.
Example: Several CIS countries rely on Russia as their main export market.
It was created by the leaders of Russia, Ukraine and Belarus in the Belovezha Accords and joined by most other republics later that month. The Baltic states never joined; Georgia withdrew in 2009 and Ukraine ended its participation in 2018. Its integration has been limited, and Russia-led bodies such as the Eurasian Economic Union have overshadowed it.
3. Cosine plus i sine (cis)
Units & Measurements · Math Abbreviations
Shorthand for cos θ + i sin θ, used to write complex numbers in polar form: z = r cis θ. By Euler's formula, cis θ equals e^(iθ).
Example: The cube roots of 8 are 2 cis 0°, 2 cis 120° and 2 cis 240°.
The notation is common in precalculus and engineering textbooks, though university courses usually prefer e^(iθ). Multiplying numbers in cis form multiplies their moduli and adds their angles, which makes De Moivre's theorem easy to state.
Related abbreviations
More neurology abbreviations
- BE-FAST – Balance, Eyes, Face, Arm, Speech, Time
- CAA – Cerebral amyloid angiopathy
- cEEG – Continuous electroencephalography
- CIDP – Chronic inflammatory demyelinating polyneuropathy
- CJD – Creutzfeldt-Jakob disease
- CMT – Charcot-Marie-Tooth disease
- CP – Cerebral palsy
- CPP – Cerebral perfusion pressure
See all 131 neurology abbreviations →
More international organization abbreviations
- BIS – Bank for International Settlements
- BRICS – Brazil, Russia, India, China, South Africa
- CARICOM – Caribbean Community
- CERN – European Organization for Nuclear Research
- CITES – Convention on International Trade in Endangered Species of Wild…
- CoE – Council of Europe
- COP – Conference of the Parties
- CPTPP – Comprehensive and Progressive Agreement for Trans-Pacific Partnership
See all 108 international organization abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.