Fn
Abbreviation with 4 meanings
| Stands for | Function key (modifier) |
|---|---|
| Meanings | 4 |
| Categories | Technology & Computing, Medical, Writing & Everyday, Military |
| Also written | FN, fn. |
Fn has four meanings. The most common are Function key (modifier) (computer) and Febrile neutropenia (hematology and oncology); it can also stand for Footnote and Fireman.
Meanings of Fn at a glance
| # | Fn stands for | Context |
|---|---|---|
| 1 | Function key (modifier) | Technology & Computing › Computer |
| 2 | Febrile neutropenia | Medical › Hematology and Oncology |
| 3 | Footnote | Writing & Everyday › Citation and Bibliography |
| 4 | Fireman | Military › US Navy and Coast Guard Rank |
1. Function key (modifier)
Technology & Computing · Computer Abbreviations
Modifier key on laptops and compact keyboards that activates the secondary functions printed on other keys, such as screen brightness, volume or the F1 to F12 keys. Unlike Ctrl or Alt, it is handled inside the keyboard itself, so the operating system usually cannot remap it.
Example: Press Fn+F5 to turn on the keyboard backlight.
Not to be confused with the row of F1 to F12 "function keys". Many laptops offer Fn Lock so the top row defaults to either media controls or F-keys. On recent Apple keyboards the Fn key doubles as a globe key that switches input languages and opens the emoji picker. Its placement in the bottom-left corner on some laptops annoys users who expect Ctrl there.
2. Febrile neutropenia (FN)
Medical · Hematology and Oncology Abbreviations
Fever of 38.3 degrees Celsius or higher, or 38.0 sustained for an hour, in a patient whose absolute neutrophil count is below 500 per microliter or expected to fall below it, usually after chemotherapy. It is an oncologic emergency because infections can progress rapidly.
Example: Day 10 after chemo, temp 38.6, ANC 200: FN, cefepime within 60 minutes of triage.
Guidelines recommend broad-spectrum antibiotics with activity against Pseudomonas within an hour of presentation. The MASCC score identifies low-risk patients who may be treated as outpatients with oral antibiotics. Prophylactic G-CSF is recommended when a chemotherapy regimen carries a 20 percent or greater risk of febrile neutropenia.
3. Footnote (fn.)
Writing & Everyday · Citation and Bibliography Abbreviations
Cites a footnote by number in citations, cross-references and editing comments, as in "see fn. 12." Lawyers and editors use it more than academic style guides do.
Example: As noted in fn. 7, the earlier draft of the contract did not include the arbitration clause.
Most citation styles prefer n. for referring to notes. Footnotes sit at the bottom of the page, while endnotes are gathered at the end of a chapter or book. On laptop keyboards, Fn is a modifier key that unlocks secondary functions, an unrelated meaning.
4. Fireman (FN)
Military · US Navy and Coast Guard Rank Abbreviations
Engineering-group apprentice rank at pay grade E-3 in the Navy and Coast Guard, recognized by three red diagonal stripes. Firemen work in engine rooms and auxiliary spaces on their way to ratings such as machinist's mate, engineman, electrician's mate and hull maintenance technician.
Example: FN Ortiz qualified as a sounding-and-security watchstander in the main engine room.
The title survives from the days of coal-fired boilers, when firemen stoked the fires; it has nothing to do with firefighting, which falls to damage controlmen. A designated fireman writes the rating first, as in MMFN. The E-2 and E-1 forms are Fireman Apprentice (FA) and Fireman Recruit (FR).
Related abbreviations
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More hematology and oncology abbreviations
- FFP – Fresh frozen plasma
- FISH – Fluorescence in situ hybridization
- FL – Follicular lymphoma
- FLOT – Fluorouracil, leucovorin, oxaliplatin, docetaxel
- FOLFIRI – Folinic acid (leucovorin), fluorouracil, irinotecan
- FOLFIRINOX – Folinic acid, fluorouracil, irinotecan, oxaliplatin
- FOLFOX – Folinic acid (leucovorin), fluorouracil, oxaliplatin
- FVL – Factor V Leiden
See all 144 hematology and oncology abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.