thermionic valve
"thermionic-valve" is a 15-letter English headword indexed on PlainSpell.
The verdict
“thermionic valve” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.
- Unranked
- below top-frequency English
- 16
- letters
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - An electronic device incorporating electrons from a glowing cathode inside an evacuated glass tube, functioning as a switch, amplifier etc.
Corpus desk
Index EN-thermionic-valve · thermionic valve · English
thermionic valve · unranked · 0 variants · 0 confusables
- FREQ-UNRANKED Unranked
- LEN-MEGA 16 letters
- VOW-6 6 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-THIN "T" thin
- PHOTO-UNK Peer pending
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.
| Property | Value |
|---|---|
| Headword | thermionic valve |
| Language | English |
| Part of speech | Noun |
| Letters | 16 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “thermionic valve” in English
Rare enough to double-check
thermionic valve is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "An electronic device incorporating electrons from a glowing cathode inside an evacuated glass tube, functioning as a switch, amplifier etc.".
We couldn't generate a plausible misspelling set for thermionic valve, since its letter pattern doesn't lend itself to common typo substitutions. No close-neighbour confusable shows up for this headword in our dataset, which usually means its spelling is distinct enough that readers don't reach for a similar-looking word instead.
Our source data has no etymology on file for this entry, so its spelling is best explained by sound-to-letter mapping rather than etymology. The correct English form is thermionic valve, spelled T-H-E-R-M-I-O-N-I-C- -V-A-L-V-E.
Definition
- 1An electronic device incorporating electrons from a glowing cathode inside an evacuated glass tube, functioning as a switch, amplifier etc.
Recorded use
Wiktionary exampleThese source excerpts show how thermionic valve appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
The age of electronics began in 1906 with Lee De Forest's invention of the vacuum tube, or, as the British (led by John Ambrose Fleming, whose work preceded De Forest's) described it, the thermionic valve.
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.