UFO
/ˌjuːɛfˈəʊ/
"ufo" is a 3-letter English headword indexed on PlainSpell.
The verdict
“UFO” is a moderately-common English word, ranked #15,539 in English word frequency and used as a noun.
- #15,539
- frequency rank, English
- 3
- letters
- 20
- confusable pairs
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Initialism of unidentified flying object; (loosely) an alien spacecraft.
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
Spelling & Dictionary Insight
The English entry for UFO is 3 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ˌjuːɛfˈəʊ/. Corpus data places it at rank #15,539 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 3 distinct senses for this headword, so context determines which meaning a reader should apply.
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.
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.
Frequently Asked Questions
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Using “UFO”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is U-F-O - every other letter order is a misspelling in standard orthography.
- Say it as /ˌjuːɛfˈəʊ/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Don't mix it up with “up” - see the side-by-side comparison. UFO vs up
- Browse more English words and confusable pairs in the same reference. English words
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.