dihydrogen monoxide

/daɪˈhaɪdɹədʒ(ə)n məˈnɒksaɪd/

//daɪˈhaɪdɹədʒ(ə)n məˈnɒksaɪd// noun

"dihydrogen-monoxide" is a 18-letter English headword indexed on PlainSpell.

The verdict

“dihydrogen monoxide” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
19
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - H₂O, water.

Corpus desk

Index EN-dihydrogen-monoxide · dihydrogen monoxide · English

dihydrogen monoxide · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-MEGA 19 letters
  • VOW-8 8 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "D" 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.

Key facts for dihydrogen monoxide
PropertyValue
Headworddihydrogen monoxide
LanguageEnglish
Part of speechNoun
IPA/daɪˈhaɪdɹədʒ(ə)n məˈnɒksaɪd/
Letters19
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “dihydrogen monoxide” in English

dihydrogen monoxidefalls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

dihydrogen monoxide is uncommon English outside the top frequency list, classed as anoun, transcribed /daɪˈhaɪdɹədʒ(ə)n məˈnɒksaɪd/. Rarity is why readers land here mid-draft. Gloss: "H₂O, water.".

We couldn't generate a plausible misspelling set for dihydrogen monoxide, and the word's spelling is regular enough that our generator found nothing worth flagging. This entry stands alone in our confusable dataset, which tends to mean the word is visually distinctive enough to stand on its own.

No documented word history exists for this headword, so its spelling pattern is best understood through pronunciation rather than a traceable origin. The correct English form is dihydrogen monoxide, spelled D-I-H-Y-D-R-O-G-E-N- -M-O-N-O-X-I-D-E.

Definition

  1. 1
    H₂O, water.

Recorded use

Wiktionary examples

These source excerpts show how dihydrogen monoxide appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. Thus ice contracts when melting, ice being a regular and rather open structure of hydrogen and oxygen atoms, while water is a collection of dihydrogen-monoxide (H₂O), tetra-hydrogen dioxide (2H₂O), and more complex molecules.
  2. The Invisible Killer Dihydrogen monoxide is colorless, odorless, tasteless, and kills uncounted thousands of people every year. Most of these deaths are caused by accidental inhalation of DHMO, but the dangers of dihydrogen monoxide do not end there.

This word in other languages

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.

Frequently Asked Questions

How do you spell "dihydrogen monoxide"?
"dihydrogen monoxide" is spelled D-I-H-Y-D-R-O-G-E-N- -M-O-N-O-X-I-D-E. The IPA pronunciation is /daɪˈhaɪdɹədʒ(ə)n məˈnɒksaɪd/.
What does "dihydrogen monoxide" mean?
As a noun, "dihydrogen monoxide" means: H₂O, water.
How do you pronounce "dihydrogen monoxide"?
The IPA (International Phonetic Alphabet) transcription for "dihydrogen monoxide" is /daɪˈhaɪdɹədʒ(ə)n məˈnɒksaɪd/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What language does "dihydrogen monoxide" come from?
"dihydrogen monoxide" is a English word. PlainSpell covers definitions, pronunciations, and spelling data across English, Spanish, Portuguese, French, and German.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list