decennium
/dɪˈsɛnɪəm/
"decennium" is a 9-letter English headword indexed on PlainSpell.
The verdict
“decennium” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.
- Unranked
- below top-frequency English
- 9
- letters
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Synonym of decade: a ten year period.
Corpus desk
Index EN-decennium · decennium · English
decennium · unranked · 0 variants · 0 confusables
- FREQ-UNRANKED Unranked
- LEN-LONG 9 letters
- VOW-4 4 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.
| Property | Value |
|---|---|
| Headword | decennium |
| Language | English |
| Part of speech | Noun |
| IPA | /dɪˈsɛnɪəm/ |
| Letters | 9 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “decennium” in English
Rare enough to double-check
decennium is uncommon English outside the top frequency list, classed as anoun, transcribed /dɪˈsɛnɪəm/. Rarity is why readers land here mid-draft. Gloss: "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.
Recorded use
Wiktionary examplesThese source excerpts show how decennium appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
G.B. still has to cope with the heritage of approx. 20 years of consecutive Conservative reigns, just as you guys are getting your act together after almost a decennium of Enlightened Ronnie.
Christian leaders refused even to *look* through Galileo's telescope (as a matter of fact, the Vatican cleared Galileo's name only as late as in the previous decennium).
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.