UFO
/ˌjuːɛfˈəʊ/
"ufo" is a 3-letter English headword indexed on PlainSpell.
The verdict
“UFO” sits in 20 confusable pairs (corpus #15,539) as a noun. The look-alike neighbours are the real trap.
- #15,539
- frequency rank, English
- 1,433
- “U” headwords
- 20
- confusable pairs
According to Wiktionary data (CC BY-SA, analyzed September 2, 2026) - Initialism of unidentified flying object; (loosely) an alien spacecraft.
Corpus desk
Index EN-ufo · UFO · English
UFO · rank #15,539 · 0 variants · 20 confusables
- FREQ-MID #15,539
- LEN-MID 3 letters
- VOW-2 2 vowels
- CONFUS-HIGH 20 pairs
- VAR-0 0 variants
- BOOK-MID 1,433
- PHOTO-FINISH twenties
Nearest frequency peer: twenties (-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 “UFO”
Lower corpus rank = more everyday usage (inverted bar length for readability)
- triggering
triggering
84,465 corpus weight
- Tulsa
Tulsa
84,464 corpus weight
- twenties
twenties
84,463 corpus weight
- UFO
UFO
84,462 corpus weight
- uncover
uncover
84,461 corpus weight
- unnatural
unnatural
84,460 corpus weight
What this shows Bars show where “UFO” sits against the nearest ranked English headwords in the FrequencyWords band, not a reprint of letter-browse containment.
Visual similarity to commonly confused words
How many letter changes separate each confused pair (Levenshtein distance, normalized).
Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).
| Property | Value |
|---|---|
| Headword | UFO |
| Language | English |
| Part of speech | Noun |
| IPA | /ˌjuːɛfˈəʊ/ |
| Letters | 3 |
| Frequency rank | #15,539 |
| Misspellings tracked | 0 |
| Confusable pairs | 20 |
| Source | Wiktionary (kaikki.org) |
Where “UFO” sits in English frequency
Easy to mix with look-alikes
The spelling risk for UFO is neighbouring look-alikes ("up", "us", …), not just typos; it is anoun pronounced /ˌjuːɛfˈəʊ/. Frequency #15,539 among 1,433 “U” headwords. 3 recorded senses keep meaning in play.
Zero misspellings are on record for UFO in our index, typically a sign the spelling maps closely to how the word sounds. It also participates in 20 confusable-pair relationships, "up", "us", "UK", and more, since the words sound or look close enough that writers reach for the wrong one mid-sentence.
Etymologically, the entry records: Abbreviations. The correct English form is UFO, spelled U-F-O.
Definition
- 1Initialism of unidentified flying object; (loosely) an alien spacecraft.
- 2An "unfinished object" in knitting or other kinds of craft.
- 3Initialism of ultrared flattened object.
Recorded use
Wiktionary examplesThese source excerpts show how UFO appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
After the case had been reported in the newspapers, Mrs. Gracindo de Souza, wife of a member of the local stock exchange, told police that she and her daughter had been driving down Alameda Sao Boaventura when they had seen an^([sic]) UFO hovering over the clearing where the bodies were later discovered.
To my way of thinking, there is every bit as much evidence for the existence of UFOs as there is for the existence of God. Probably far more. At least in the case of UFOs there have been countless taped and filmed—and, by the way, unexplained—sightings from all over the world, along with documented radar evidence seen by experienced military and civilian…
Etymology
Abbreviations.
This word in other languages
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
How do you spell "UFO"?
What does "UFO" mean?
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Similar English words by spelling shape
Same letter count and similar misspelling depth for "UFO", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 3 letters (nearest by frequency rank).
What to do next
You've looked up "UFO". Here's where to go from here.
- "UFO" maps to 20 confusable pairs in this vintage; the highest-scored is "up". View pair
- Usage frequency rank #15,539 among English headwords in this corpus. Corpus statistics
- Browse more English words in the "U" letter cohort. U–Z browse
PlainSpell is a reference corpus, not spelling advice. Verify unusual forms in context.
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.