diphtheria
/dɪfˈθɪə.ɹi.ə/
Detailed reference entry for the English word "diphtheria", 10-letters, with pronunciation in International Phonetic Alphabet notation, etymology traced through Germanic and Romance roots where applicable, common misspelling variants catalogued from Wiktionary, and usage frequency ranked against an open word-frequency list covering the top 100,000 English words. PlainSpell covers English, Spanish, Portuguese, French, and German spelling with confusable-pair detection that highlights visually and phonetically similar words. This entry for "diphtheria" includes synonyms, antonyms, homophones, and cross-language translation pointers sourced from Wiktionary via the kaikki.org extract. Whether you are verifying the correct spelling of "diphtheria" for academic writing, checking homophone confusion, or exploring etymological origins, this page provides a citation-backed, free reference that requires no sign-up.
The verdict
“diphtheria” is a moderately-common English word, ranked #44,165 in English word frequency and used as a noun.
- #44,165
- frequency rank, English
- 10
- letters
- 15
- tracked misspellings
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A serious infectious disease leading to inflammation of mucous membranes of the upper respiratory tract, caused by Corynebacterium diphtheriae.
Compare similar words
See how diphtheria compares against similar English words.
Browse all word comparisons →| Property | Value |
|---|---|
| Headword | diphtheria |
| Language | English |
| Part of speech | Noun |
| IPA | /dɪfˈθɪə.ɹi.ə/ |
| Letters | 10 |
| Frequency rank | #44,165 |
| Misspellings tracked | 15 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “diphtheria” sits in English frequency
Spelling & Dictionary Insight
The English entry for diphtheria is 10 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /dɪfˈθɪə.ɹi.ə/. Corpus data places it at rank #44,165 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. The dominant gloss from Wiktionary reads: "A serious infectious disease leading to inflammation of mucous membranes of the upper respiratory tract, caused by Corynebacterium diphtheriae.".
Our generated misspelling index lists 15 likely wrong-spelling variants for diphtheria, with forms such as "ddiphtheria", "dihptheria", and "diphhteria". Each variant is a distinct typo pattern an edit-distance generator flags, typically a doubled-consonant error, a silent-letter drop, or a vowel substitution. It is not paired with a close-neighbour confusable in our dataset, which tends to mean the word is visually distinctive enough to stand on its own.
Etymologically, the entry records: From French diphtérie (later for a while also spelled diphthérie) in 1857, which was coined in 1855 with the suffix -ie to replace -ite in the previous term diphtérite for the disease because it affects more than one part of the body. The previous term (lat… Root origin matters for spelling because borrowed morphemes (Greek, Latin, Old French, Old English) carry their source-language orthographic conventions into modern English, which is why historical etymology is often the cleanest predictor of whether a cluster like "-ough", "-eau", or "-tion" will appear. For readers arriving here from a spelling check, the authoritative guidance is: the correct English form is diphtheria, spelled D-I-P-H-T-H-E-R-I-A, and any other sequence of those letters, regardless of how natural it feels, is a misspelling in standard orthography.
Definition
- 1A serious infectious disease leading to inflammation of mucous membranes of the upper respiratory tract, caused by Corynebacterium diphtheriae.
Etymology
From French diphtérie (later for a while also spelled diphthérie) in 1857, which was coined in 1855 with the suffix -ie to replace -ite in the previous term diphtérite for the disease because it affects more than one part of the body. The previous term (later for a while also spelled diphthérite) was coined in 1817 by Pierre Bretonneau using Ancient Greek διφθέρα (diphthéra, “prepared hide, leather”) in reference to the tough membrane that forms in the throat. Bretonneau perhaps coined and used the Latin term diphtheritis (with its close imitation of Greek spelling typical of Neolatin) even earlier than the French term diphtérite, which follows the French habit of sometimes spelling t for the Latin transliteration th of Greek θ (but not, for example, in thermomètre).
Synonyms
This word in other languages
Common misspellings
Also misspelled as: ddiphtheria,dihptheria,diphhteria,diphhtheria,diphtehria,diphtheira,diphtherai,diphtherria,diphthheria,diphthreia,diphttheria,dipphtheria,dipthheria,dpihtheria,idphtheria
Misspelling Pattern Breakdown
How far each generated variant is from the correct spelling of diphtheria - measured in single-character edits (insert, delete, or substitute a letter). Larger bars are easier to catch; one-edit slips are the sneakiest.
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.
Cite this page
Free to reuse with attribution (CC BY-SA). Copy the citation:
PlainSpell, “diphtheria, English word data” (May 6, 2026). Derived from Wiktionary (kaikki.org, CC BY-SA) and an open word-frequency list. https://plainspell.com/en/word/diphtheria
Frequently Asked Questions
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Using “diphtheria”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is D-I-P-H-T-H-E-R-I-A - every other letter order is a misspelling in standard orthography.
- Say it as /dɪfˈθɪə.ɹi.ə/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Browse more English words and confusable pairs in the same reference. English words
Nearby English words
Other entries that begin with the letter D in our English index: