decennium
/dɪˈsɛnɪəm/
"decennium" is a 9-letter English headword indexed on PlainSpell.
The verdict
“decennium” is outside the top-ranked English vocabulary, used as a noun - the kind of word writers most often double-check.
- Unranked
- below top-frequency English
- 9
- letters
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Synonym of decade: a ten year period.
| Property | Value |
|---|---|
| Headword | decennium |
| Language | English |
| Part of speech | Noun |
| IPA | /dɪˈsɛnɪəm/ |
| Letters | 9 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “decennium” sits in English frequency
Spelling & Dictionary Insight
The English entry for decennium is 9 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /dɪˈsɛnɪəm/. It sits outside the most-frequent rank tiers, which is often why uncommon words generate more spelling variants per reader. The dominant gloss from Wiktionary reads: "Synonym of decade: a ten year period.".
Our edit-distance generator produced no likely misspellings for decennium, suggesting the orthography follows predictable English patterns. No confusable counterpart is on file for this word, since no other headword is close enough in sound or shape to pair with it.
Etymologically, the entry records: From Latin decennium, from decennis (“10-year”) + -ium (suffix forming abstract nouns), from deciēs (“ten times”) + annus (“year”) + -is (suffix forming compound adjectives). Equivalent to decennial + -ium. The correct English form is decennium, spelled D-E-C-E-N-N-I-U-M.
Definition
- 1Synonym of decade: a ten year period.
Etymology
From Latin decennium, from decennis (“10-year”) + -ium (suffix forming abstract nouns), from deciēs (“ten times”) + annus (“year”) + -is (suffix forming compound adjectives). Equivalent to decennial + -ium.
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
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Using “decennium”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is D-E-C-E-N-N-I-U-M - every other letter order is a misspelling in standard orthography.
- Say it as /dɪˈsɛnɪəm/ (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
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.