ionosphere

noun

By · According to Wiktionary data (CC BY-SA) ·

"ionosphere" is a 10-letter English headword indexed on PlainSpell.

The verdict

“ionosphere” is uncommon English (frequency #54,860 among 17,902 “I” headwords), classed as a noun. The kind of spelling people second-guess.

#54,860
frequency rank, English
17,902
“I” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - The part of the Earth's atmosphere beginning at an altitude of about 50 kilometers (31 miles) and extending outward 500 kilometers (310 miles) or more.

Key facts for ionosphere
PropertyValue
Headwordionosphere
LanguageEnglish
Part of speechNoun
Letters10
Frequency rank#54,860
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “ionosphere” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). ionosphere lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Rare enough to double-check

ionosphere is uncommon English at frequency #54,860 among 17,902 “I” headwords, classed as anoun. Rarity is why readers land here mid-draft. 2 senses are on record.

No misspelling variants are generated for ionosphere in our index, a straightforward case of a spelling with little room for common typos. No confusable counterpart is on file for this word, since nothing in our dataset looks or sounds close enough to cause mix-ups.

Etymologically, the entry records: From iono- + -sphere. The correct English form is ionosphere, spelled I-O-N-O-S-P-H-E-R-E.

Definition

  1. 1
    The part of the Earth's atmosphere beginning at an altitude of about 50 kilometers (31 miles) and extending outward 500 kilometers (310 miles) or more.
  2. 2
    The similar region of the atmosphere of another planet.

Etymology

From iono- + -sphere.

This word in other languages

ionosfera(Español)ionosphère(Français)Ionosphäre(Deutsch)ionosfera(Português)

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "ionosphere"?
"ionosphere" is spelled I-O-N-O-S-P-H-E-R-E.
What does "ionosphere" mean?
As a noun, "ionosphere" means: The part of the Earth's atmosphere beginning at an altitude of about 50 kilometers (31 miles) and extending outward 500 kilometers (310 miles) or more.
What is the origin of the word "ionosphere"?
From iono- + -sphere. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “ionosphere”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is I-O-N-O-S-P-H-E-R-E - every other letter order is a misspelling in standard orthography.
  • Browse more English words and confusable pairs in the same reference. English words

Other uncommon English words near this rank

Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list