POSIX
/ˈpɒz.ɪks/
"posix" is a 5-letter English headword indexed on PlainSpell.
The verdict
“POSIX” is uncommon English (frequency #74,404 among 4,417 “P” headwords), classed as a proper noun. The kind of spelling people second-guess.
- #74,404
- frequency rank, English
- 4,417
- “P” headwords
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Acronym of Portable Operating System Interface, a set of IEEE standards designed to provide application portability between Unix variants.
Corpus desk
Index EN-posix · POSIX · English
POSIX · rank #74,404 · 0 variants · 0 confusables
- FREQ-RARE #74,404
- LEN-MID 5 letters
- VOW-2 2 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-MID 4,417
- PHOTO-FINISH pouncing
Nearest frequency peer: pouncing (+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 “POSIX”
Sparse band: bars invert rank so rarer forms read shorter
- pointlessly
pointlessly
25,600 corpus weight
- POSIX
POSIX
25,597 corpus weight
- pouncing
pouncing
25,596 corpus weight
- pred
pred
25,595 corpus weight
- preprint
preprint
25,594 corpus weight
- prepubescent
prepubescent
25,593 corpus weight
What this shows Long-tail view: where “POSIX” sits against similarly uncommon English ranks.
| Property | Value |
|---|---|
| Headword | POSIX |
| Language | English |
| Part of speech | Proper noun |
| IPA | /ˈpɒz.ɪks/ |
| Letters | 5 |
| Frequency rank | #74,404 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “POSIX” in English
Rare enough to double-check
POSIX is uncommon English at frequency #74,404 among 4,417 “P” headwords, classed as aproper noun, transcribed /ˈpɒz.ɪks/. Rarity is why readers land here mid-draft. Gloss: "Acronym of Portable Operating System Interface, a set of IEEE standards designed to provide application portability between Unix variants.".
The misspelling generator found no plausible variants for POSIX, a straightforward case of a spelling with little room for common typos. We don't track a confusable pairing for this entry, since no other headword is close enough in sound or shape to pair with it.
No documented word history exists for this headword, leaving phoneme-to-grapheme mapping as the best guide to its spelling rather than a borrowing history. The correct English form is POSIX, spelled P-O-S-I-X.
Definition
- 1Acronym of Portable Operating System Interface, a set of IEEE standards designed to provide application portability between Unix variants.
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 "POSIX", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 5 letters (nearest by frequency rank).