F region

noun

: the highest region of the ionosphere occurring from 80 miles (130 kilometers) to more than 300 miles (500 kilometers)

Word History

First Known Use

1923, in the meaning defined above

Time Traveler
The first known use of F region was in 1923

Browse Nearby Entries

Cite this Entry

“F region.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/F%20region. Accessed 28 Feb. 2025.

More from Merriam-Webster on F region

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!