noun
- The highest region of the ionosphere (from 90 to 600 miles up) which contains the highest concentration of free electrons and is most useful for long-range radio transmission.
- synonyms: Appleton layer, F layer
WordNet 3.0 © 2006 by Princeton University
| APA | WordNet. (2010). f region. Retrieved September 23, 2026, from http://smartdefine.org/f_region/definitions/1274296 |
| Chicago | WordNet. 2010. "f region" http://smartdefine.org/f_region/definitions/1274296 (accessed September 23, 2026). |
| Harvard | WordNet 2010, f region, Smart Define, viewed 23 September, 2026, <http://smartdefine.org/f_region/definitions/1274296>. |
| MLA | WordNet. "f region" 23 October 2010. Web. 23 September 2026. <http://smartdefine.org/f_region/definitions/1274296> |