IOU
"iou" is a 3-letter English headword indexed on PlainSpell.
The verdict
“IOU” is uncommon English (frequency #69,965 among 2,140 “I” headwords), classed as a phrase. The kind of spelling people second-guess.
- #69,965
- frequency rank, English
- 2,140
- “I” headwords
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - I owe you.
Corpus desk
Index EN-iou · IOU · English
IOU · rank #69,965 · 0 variants · 0 confusables
- FREQ-RARE #69,965
- LEN-MID 3 letters
- VOW-3 3 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-MID 2,140
- PHOTO-FINISH Iscariot
Nearest frequency peer: Iscariot (+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 “IOU”
Sparse band: bars invert rank so rarer forms read shorter
- intermedia
intermedia
30,041 corpus weight
- intrastate
intrastate
30,039 corpus weight
- invisibly
invisibly
30,038 corpus weight
- IOU
IOU
30,036 corpus weight
- Iscariot
Iscariot
30,035 corpus weight
- Islamization
Islamization
30,034 corpus weight
What this shows Long-tail view: where “IOU” sits against similarly uncommon English ranks.
| Property | Value |
|---|---|
| Headword | IOU |
| Language | English |
| Part of speech | Phrase |
| Letters | 3 |
| Frequency rank | #69,965 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “IOU” in English
Rare enough to double-check
IOU is uncommon English at frequency #69,965 among 2,140 “I” headwords, classed as aphrase. Rarity is why readers land here mid-draft. Gloss: "I owe you.".
Zero misspellings are on record for IOU in our index, since its letter sequence doesn't invite the usual edit-distance slips. Our confusable-pair dataset has no match for it, which tends to mean the word is visually distinctive enough to stand on its own.
Etymologically, the entry records: From the pronunciation of "I owe you". Attested since at least 1618. The correct English form is IOU, spelled I-O-U.
Definition
- 1I owe you.
Recorded use
Wiktionary exampleThese source excerpts show how IOU appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
Customarily, if you borrow $10 for lunch from a coworker, writing IOU $10 on a yellow sticky note acts as a legal promissory note that you will repay said amount on payday.
Etymology
From the pronunciation of "I owe you". Attested since at least 1618.
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 "IOU", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 3 letters (nearest by frequency rank).