ultrabook
"ultrabook" is a 9-letter English headword indexed on PlainSpell.
The verdict
“ultrabook” is uncommon English (frequency #86,886 among 23,789 “U” headwords), classed as a noun. The kind of spelling people second-guess.
- #86,886
- frequency rank, English
- 23,789
- “U” headwords
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A very lightweight and thin portable computer the areal size of a notebook computer or subnotebook.
| Property | Value |
|---|---|
| Headword | ultrabook |
| Language | English |
| Part of speech | Noun |
| Letters | 9 |
| Frequency rank | #86,886 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “ultrabook” sits in English frequency
Rare enough to double-check
ultrabook is uncommon English at frequency #86,886 among 23,789 “U” headwords, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "A very lightweight and thin portable computer the areal size of a notebook computer or subnotebook.".
ultrabook has no tracked misspelling variants, since its letter sequence doesn't invite the usual edit-distance slips. This entry stands alone in our confusable dataset, a sign it's visually distinctive enough not to be mixed up with another word.
Etymologically, the entry records: From ultra- + book; see notebook computer. The correct English form is ultrabook, spelled U-L-T-R-A-B-O-O-K.
Definition
- 1A very lightweight and thin portable computer the areal size of a notebook computer or subnotebook.
Etymology
From ultra- + book; see notebook computer.
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
How do you spell "ultrabook"?
What does "ultrabook" mean?
What is the origin of the word "ultrabook"?
Is PlainSpell free to use?
Using “ultrabook”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is U-L-T-R-A-B-O-O-K - 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.