SFO
"sfo" is a 3-letter English headword indexed on PlainSpell.
The verdict
“SFO” sits in 20 confusable pairs (corpus #42,889) as a proper noun. The look-alike neighbours are the real trap.
- #42,889
- frequency rank, English
- 6,566
- “S” headwords
- 20
- confusable pairs
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Initialism of Serious Fraud Office.
Corpus desk
Index EN-sfo · SFO · English
SFO · rank #42,889 · 0 variants · 20 confusables
- FREQ-MID #42,889
- LEN-MID 3 letters
- VOW-1 1 vowel
- CONFUS-HIGH 20 pairs
- VAR-0 0 variants
- BOOK-DENSE 6,566
- PHOTO-FINISH sepulchre
Nearest frequency peer: sepulchre (-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 neighbours of confusable “SFO”
Peers at similar corpus weight, separate from look-alike pairs below
- Semite
Semite
57,115 corpus weight
- sepulchre
sepulchre
57,113 corpus weight
- SFO
SFO
57,112 corpus weight
- shill
shill
57,109 corpus weight
- shorted
shorted
57,107 corpus weight
- sich
sich
57,106 corpus weight
What this shows Bars place “SFO” against nearest ranked English headwords, not a reprint of the confusable-pair desk.
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 | SFO |
| Language | English |
| Part of speech | Proper noun |
| Letters | 3 |
| Frequency rank | #42,889 |
| Misspellings tracked | 0 |
| Confusable pairs | 20 |
| Source | Wiktionary (kaikki.org) |
Corpus rank beside confusables of “SFO”
Easy to mix with look-alikes
The spelling risk for SFO is neighbouring look-alikes ("so", "SI", …), not just typos; it is aproper noun. Frequency #42,889 among 6,566 “S” headwords. 2 recorded senses keep meaning in play.
SFO doesn't appear in our generated misspelling index, a sign its spelling follows regular English conventions. It also participates in 20 confusable-pair relationships, "so", "SI", "SS", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.
Our source data has no etymology on file for this entry, 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 SFO, spelled S-F-O.
Definition
- 1Initialism of Serious Fraud Office.
- 2Abbreviation of San Francisco International Airport.
Recorded use
Wiktionary exampleThese source excerpts show how SFO appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
I emerge out of the tunnel into the pale glow of SFO, the spinning wheels and striding shoes and TV news on low, toddlers screaming with joy or pain, the overlapping echo of flight announcements.
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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Similar English words by spelling shape
Same letter count and similar misspelling depth for "SFO", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 3 letters (nearest by frequency rank).