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 2,140 “I” headwords), classed as a noun. The kind of spelling people second-guess.

#54,860
frequency rank, English
2,140
“I” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 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.

Corpus desk

Index EN-ionosphere · ionosphere · English

ionosphere · rank #54,860 · 0 variants · 0 confusables

  • FREQ-RARE #54,860
  • LEN-MEGA 10 letters
  • VOW-5 5 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 2,140
  • PHOTO-FINISH invincibility

Nearest frequency peer: invincibility (-1 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Long-tail ranks near “ionosphere”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “ionosphere” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for ionosphere
PropertyValue
Headwordionosphere
LanguageEnglish
Part of speechNoun
Letters10
Frequency rank#54,860
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “ionosphere” in English

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

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

The axis is logarithmic, with each marked tick roughly ten times rarer than the last. Rare peers in the same band: “invincibility” (#54,859), “interurban” (#54,856), “Jaffna” (#54,864). Among 2,140 “I” headwords, “ionosphere” is #54,860. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

ionosphere is uncommon English at frequency #54,860 among 2,140 “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.

Recorded use

Wiktionary examples

These source excerpts show how ionosphere appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. Dave frowned as he tried to answer. "Well, I suppose the atmosphere is oxygen and nitrogen, mostly; then there's the ionosphere and the ozone layer. As I remember, the color of the sky is due to the scattering of light—light rays being diffracted in the air."
  2. Solar storms drive currents of millions of amps through the electrically conductive upper layer of our atmosphere (known as the ionosphere). These currents, which can fluctuate rapidly, drive powerful magnetic disturbances at the Earth's surface that in turn induce electrical currents in the planet's crust.

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.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "ionosphere", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 10 letters (nearest by frequency rank).

interurban#54,856homozygous#54,839kinematics#54,885lamentable#54,892

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

Source: FrequencyWords open word-frequency list