radii
/ˈɹeɪ.di.aɪ/
"radii" is a 5-letter English headword indexed on PlainSpell.
The verdict
“radii” is uncommon English (frequency #50,177 among 3,094 “R” headwords), classed as a noun. The kind of spelling people second-guess.
- #50,177
- frequency rank, English
- 3,094
- “R” headwords
According to Wiktionary data (CC BY-SA, analyzed September 2, 2026) - plural of radius
Corpus desk
Index EN-radii · radii · English
radii · rank #50,177 · 0 variants · 0 confusables
- FREQ-RARE #50,177
- LEN-MID 5 letters
- VOW-3 3 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-MID 3,094
- PHOTO-FINISH Raikkonen
Nearest frequency peer: Raikkonen (+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.
Frequency neighbourhood for “radii”
Lower corpus rank = more everyday usage (inverted bar length for readability)
- Puebla
Puebla
49,832 corpus weight
- purveyor
purveyor
49,829 corpus weight
- quinta
quinta
49,827 corpus weight
- radii
radii
49,824 corpus weight
- Raikkonen
Raikkonen
49,823 corpus weight
- recalcitrant
recalcitrant
49,818 corpus weight
What this shows Bars show where “radii” sits against the nearest ranked English headwords in the FrequencyWords band, not a reprint of letter-browse containment.
| Property | Value |
|---|---|
| Headword | radii |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈɹeɪ.di.aɪ/ |
| Letters | 5 |
| Frequency rank | #50,177 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “radii” sits in English frequency
Rare enough to double-check
radii is uncommon English at frequency #50,177 among 3,094 “R” headwords, classed as anoun, transcribed /ˈɹeɪ.di.aɪ/. Rarity is why readers land here mid-draft. Gloss: "plural of radius".
We couldn't generate a plausible misspelling set for radii, which points to an orthography that plays by predictable English rules. It is not paired with a close-neighbour confusable in our dataset, a sign it's visually distinctive enough not to be mixed up with another word.
This headword's origin isn't recorded in our source data, so spelling patterns must be inferred from the word's phoneme-to-grapheme mapping rather than from a documented borrowing chain. The correct English form is radii, spelled R-A-D-I-I.
Definition
- 1plural of radius
Recorded use
Wiktionary examplesThese source excerpts show how radii appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
The radius of the Sun is equal to about 109 Earth radii.
Now the centrifugal forces of bodies revolving in the ſame time in different circles being to one another as the radii of the circles (as ſhall be ſhewn when I come to treat of thoſe forces) it follows that the centrifugal force muſt be greateſt at the æquator, and thence be continually diminished towards the poles.
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.
PlainSpell is rendered directly from structured Wiktionary extracts and open word-frequency lists, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of September 2, 2026. Primary sources: Wiktionary (via kaikki.org) and FrequencyWords.
Frequently Asked Questions
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Similar English words by spelling shape
Same letter count and similar misspelling depth for "radii", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 5 letters (nearest by frequency 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.