terahertz
"terahertz" is a 9-letter English headword indexed on PlainSpell.
The verdict
“terahertz” is uncommon English (frequency #75,485 among 27,828 “T” headwords), classed as a noun. The kind of spelling people second-guess.
- #75,485
- frequency rank, English
- 27,828
- “T” headwords
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A unit of measurement based on one trillion hertz.
| Property | Value |
|---|---|
| Headword | terahertz |
| Language | English |
| Part of speech | Noun |
| Letters | 9 |
| Frequency rank | #75,485 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “terahertz” sits in English frequency
Rare enough to double-check
terahertz is uncommon English at frequency #75,485 among 27,828 “T” headwords, classed as anoun. Rarity is why readers land here mid-draft. 2 senses are on record.
terahertz doesn't appear in our generated misspelling index, a sign its spelling follows regular English conventions. No confusable counterpart is on file for this word, which usually means its spelling is distinct enough that readers don't reach for a similar-looking word instead.
Etymologically, the entry records: From tera- + hertz. The correct English form is terahertz, spelled T-E-R-A-H-E-R-T-Z.
Definition
- 1A unit of measurement based on one trillion hertz.
- 2One trillion hertz, 10¹² Hz.
Etymology
From tera- + hertz.
Synonyms
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 "terahertz"?
What does "terahertz" mean?
What is the origin of the word "terahertz"?
Is PlainSpell free to use?
Using “terahertz”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is T-E-R-A-H-E-R-T-Z - 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.