SN
Abbreviation with 8 meanings
| Stands for | Seaman |
|---|---|
| Meanings | 8 |
| Categories | Military, Science & Engineering, Medical, Geography & Places, Texting & Internet Slang, Writing & Everyday |
| Also written | s.n., Sn |
SN has eight meanings. The most common are Seaman (US Navy and coast guard rank) and Supernova (astronomy & Space); it can also stand for Tin, Skilled nursing, Student nurse, Senegal and Screen name, plus 1 more listed below.
Meanings of SN at a glance
| # | SN stands for | Context |
|---|---|---|
| 1 | Seaman | Military › US Navy and Coast Guard Rank |
| 2 | Supernova | Science & Engineering › Astronomy & Space |
| 3 | Tin | Science & Engineering › Chemical Element |
| 4 | Skilled nursing | Medical › Nursing |
| 5 | Student nurse | Medical › Nursing |
| 6 | Senegal | Geography & Places › Country Code |
| 7 | Screen name | Texting & Internet Slang › Texting and Chat |
| 8 | Sine nomine (without name) | Writing & Everyday › Latin |
1. Seaman
Military · US Navy and Coast Guard Rank Abbreviations
Third enlisted grade (E-3) for Navy and Coast Guard sailors in the seaman apprenticeship group, worn as three diagonal stripes. A seaman who has earned a rating is "designated" and writes it as a prefix, as in BMSN or YNSN.
Example: Undesignated SN Clark is striking for boatswain's mate while standing bridge watches.
An undesignated seaman, often called a "deck seaman," works in general duties until selecting a rating, a process called "striking." Seaman is also the generic word for any enlisted sailor. The Air Force equivalent at E-3 is Airman First Class and the Army equivalent Private First Class.
2. Supernova
Science & Engineering · Astronomy & Space Abbreviations
Powerful stellar explosion that can briefly outshine an entire galaxy. Massive stars explode when their cores collapse, and white dwarfs explode when they gain too much mass; supernovae scatter heavy elements into space and leave behind neutron stars or black holes.
Example: SN 1987A in the Large Magellanic Cloud was the first supernova whose neutrinos were detected on Earth.
Supernovae are named SN plus the year and a letter code, as in SN 2023ixf, and the plural is SNe. The last supernova seen with the naked eye in the Milky Way was Kepler's in 1604. Type Ia supernovae, with predictable peak brightness, serve as "standard candles" that revealed dark energy. Sn is also the chemical symbol for tin.
3. Tin (Sn)
Science & Engineering · Chemical Element Abbreviations
Solder, which joins nearly every electronic component, is the largest use of tin, element 50, a soft and low-melting metal also applied as a thin coating on steel food cans. Alloyed with copper it forms bronze, and with smaller amounts of copper and antimony, pewter. Below about 13 °C pure tin can slowly crumble into gray powder, called tin pest.
Example: Lead-free SAC305 solder is 96.5% Sn, 3% silver and 0.5% copper.
The symbol comes from Latin stannum, which also gives "stannous" and "stannic" in compound names. Tin from Cornwall and elsewhere was traded across the ancient world because bronze could not be made without it. The "tin can" is almost entirely steel with a micrometers-thin tin coating, and aluminum foil is still often called tinfoil.
4. Skilled nursing
Medical · Nursing Abbreviations
Home health and long-term care term for services that legally require a licensed nurse, such as wound care, injections, teaching or assessment of an unstable condition. Medicare home health covers intermittent skilled nursing when the patient is homebound.
Example: SN visits 2w4 for wound care and CHF teaching, then reassess.
Home health frequencies are written like "2w4", meaning two visits a week for four weeks. Skilled need distinguishes Medicare-covered care from custodial care such as bathing alone. Agencies document the skill provided at each SN visit to justify payment.
5. Student nurse
Medical · Nursing Abbreviations
Signature title used by nursing students documenting care during clinical rotations, written after the name with the school, such as "J. Lee, SN". Entries are typically co-signed or reviewed by the instructor or supervising RN.
Example: Vital signs obtained by A. Patel, SN, reviewed with primary RN.
Variants include NS (nursing student), SPN for student practical nurses and SRNA for student registered nurse anesthetists. Students may not take verbal orders or give certain high-alert medications without direct supervision, depending on school and hospital policy.
6. Senegal
Geography & Places · Country Code Abbreviations
Senegal, capital Dakar, alpha-3 SEN, includes the westernmost point of mainland Africa. Gorée Island off Dakar is a UNESCO site commemorating the Atlantic slave trade.
Example: Dakar, SN was chosen to host the 2026 Youth Olympic Games, the first Olympic event held in Africa.
The Paris–Dakar rally usually finished in Dakar until it moved to South America in 2009. The language code sn is Shona.
7. Screen name
Texting & Internet Slang · Texting and Chat Abbreviations
Username on AOL Instant Messenger, chat rooms and early social networks, as in "what's your sn?" Exchanging screen names was a key part of early-2000s teen social life.
Example: Add me on AIM, my sn is skaterboi99.
AOL Instant Messenger ran from 1997 until December 2017 and made screen names central to online identity. In chat, SN also means "side note." Mostly nostalgic now, replaced by "username," "handle" or "@."
8. Sine nomine (without name) (s.n.)
Writing & Everyday · Latin Abbreviations
Stands in for the publisher's name in a bibliographic record when the item does not identify one. Catalogers pair it with s.l. when both the place and the publisher are missing.
Example: The library catalog lists the broadside as "[S.l. : s.n.], ca. 1850," with no printer identified.
It appeared in square brackets under the older AACR2 cataloging rules. RDA, which the Library of Congress adopted in 2013, uses "[publisher not identified]" instead. English-language citation styles generally use n.p. for the same purpose, so s.n. is now met mostly in older catalogs and rare-book descriptions.
Related abbreviations
More US Navy and coast guard rank abbreviations
- ADM – Admiral
- AN – Airman (US Navy)
- CAPT – Captain (US Navy and Coast Guard)
- CDR – Commander
- CMDCM – Command Master Chief
- CN – Constructionman
- CPO – Chief Petty Officer
- CWO – Chief Warrant Officer
See all 31 US Navy and coast guard rank abbreviations →
More astronomy & Space abbreviations
- SETI – Search for extraterrestrial intelligence
- SKA – Square Kilometre Array
- SLS – Space Launch System
- SMBH – Supermassive black hole
- SOHO – Solar and Heliospheric Observatory
- SRB – Solid rocket booster
- SSO – Sun-synchronous orbit
- TESS – Transiting Exoplanet Survey Satellite
See all 83 astronomy & Space abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.