Help support Wordnik by adopting your favorite word!


from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The outermost region of the earth's atmosphere, consisting chiefly of ionized hydrogen.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The region of ionized hydrogen that makes up the outermost region of the Earth's atmosphere. (And by extension of other planets.)


Sorry, no etymologies found.


Sorry, no example sentences found.


Log in or sign up to get involved in the conversation. It's quick and easy.