isoniazid
/ˌʌɪ.sə(ʊ)ˈnʌɪ.əz.ɪd/
"isoniazid" is a 9-letter English headword indexed on PlainSpell.
The verdict
“isoniazid” is uncommon English (frequency #98,273 among 17,902 “I” headwords), classed as a noun. The kind of spelling people second-guess.
- #98,273
- frequency rank, English
- 17,902
- “I” headwords
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A synthetic, crystalline compound, C₆H₇N₃O, (trademarks Hydra, Hyzyd, Isovit, Laniazid, Nydrazid, Rimifon, Stanozide) used as a bacteriostatic medication in the prevention and treatment of tubercul...
Corpus desk
Index EN-isoniazid · isoniazid · English
isoniazid · rank #98,273 · 0 variants · 0 confusables
- FREQ-RARE #98,273
- LEN-LONG 9 letters
- VOW-5 5 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-DENSE 17,902
- PHOTO-FINISH isotherm
Nearest frequency peer: isotherm (+1 rank slots)
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.
Frequency neighbourhood for “isoniazid”
Lower corpus rank = more everyday usage (inverted bar length for readability)
- Ioannis
Ioannis
1,732 corpus weight
- irrelevancy
irrelevancy
1,731 corpus weight
- irritatingly
irritatingly
1,730 corpus weight
- isoniazid
isoniazid
1,728 corpus weight
- isotherm
isotherm
1,727 corpus weight
- Isère
Isère
1,726 corpus weight
What this shows Bars show where “isoniazid” sits against the nearest ranked English headwords in the FrequencyWords band, not a reprint of letter-browse containment.
| Property | Value |
|---|---|
| Headword | isoniazid |
| Language | English |
| Part of speech | Noun |
| IPA | /ˌʌɪ.sə(ʊ)ˈnʌɪ.əz.ɪd/ |
| Letters | 9 |
| Frequency rank | #98,273 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “isoniazid” sits in English frequency
Rare enough to double-check
isoniazid is uncommon English at frequency #98,273 among 17,902 “I” headwords, classed as anoun, transcribed /ˌʌɪ.sə(ʊ)ˈnʌɪ.əz.ɪd/. Rarity is why readers land here mid-draft. Gloss: "A synthetic, crystalline compound, C₆H₇N₃O, (trademarks Hydra, Hyzyd, Isovit, Laniazid, Nydrazid, Rimifon, Stanozide) used as a bacteriostatic medication in the prevention and treatment of tubercul...".
No generated misspelling entries exist for isoniazid in our index, a straightforward case of a spelling with little room for common typos. We don't track a confusable pairing for this entry, which typically means the spelling is too distinctive to be mistaken for another word.
Etymologically, the entry records: Contraction of isonicotinoylhydrazide. The correct English form is isoniazid, spelled I-S-O-N-I-A-Z-I-D.
Definition
- 1A synthetic, crystalline compound, C₆H₇N₃O, (trademarks Hydra, Hyzyd, Isovit, Laniazid, Nydrazid, Rimifon, Stanozide) used as a bacteriostatic medication in the prevention and treatment of tuberculosis.
Etymology
Contraction of isonicotinoylhydrazide.
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.
PlainSpell is rendered directly from structured Wiktionary extracts and open word-frequency lists, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 6, 2026. Primary sources: Wiktionary (via kaikki.org) and FrequencyWords.
Frequently Asked Questions
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Similar English words by spelling shape
Same letter count and similar misspelling depth for "isoniazid", not the corpus desk frequency band.
Same letter count
Frequency-ranked English headwords with 9 letters (nearest by frequency 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.