bool
"bool" is a 4-letter English headword indexed on PlainSpell.
The verdict
“bool” is uncommon English (frequency #56,624 among 31,241 “B” headwords), classed as a noun. The kind of spelling people second-guess.
- #56,624
- frequency rank, English
- 31,241
- “B” headwords
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A Boolean variable (one whose value is either true or false).
| Property | Value |
|---|---|
| Headword | bool |
| Language | English |
| Part of speech | Noun |
| Letters | 4 |
| Frequency rank | #56,624 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “bool” sits in English frequency
Rare enough to double-check
bool is uncommon English at frequency #56,624 among 31,241 “B” headwords, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "A Boolean variable (one whose value is either true or false).".
bool has no tracked misspelling variants, a sign its spelling follows regular English conventions. It is not paired with a close-neighbour confusable in our dataset, which typically means the spelling is too distinctive to be mistaken for another word.
Etymologically, the entry records: From a keyword in C++ and derived programming languages, short for Boolean. The correct English form is bool, spelled B-O-O-L.
Definition
- 1A Boolean variable (one whose value is either true or false).
Etymology
From a keyword in C++ and derived programming languages, short for Boolean.
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 “bool”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is B-O-O-L - every other letter order is a misspelling in standard orthography.
- Browse more English words and confusable pairs in the same reference. English words
Other uncommon English words near this rank
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.