thirtieth
/ˈθɜːti.əθ/
"thirtieth" is a 9-letter English headword indexed on PlainSpell.
The verdict
“thirtieth” is uncommon English (frequency #54,533 among 27,828 “T” headwords), classed as an adjective. The kind of spelling people second-guess.
- #54,533
- frequency rank, English
- 27,828
- “T” headwords
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - The ordinal form of the number thirty.
| Property | Value |
|---|---|
| Headword | thirtieth |
| Language | English |
| Part of speech | Adjective |
| IPA | /ˈθɜːti.əθ/ |
| Letters | 9 |
| Frequency rank | #54,533 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “thirtieth” sits in English frequency
Rare enough to double-check
thirtieth is uncommon English at frequency #54,533 among 27,828 “T” headwords, classed as anadjective, transcribed /ˈθɜːti.əθ/. Rarity is why readers land here mid-draft. Gloss: "The ordinal form of the number thirty.".
Our edit-distance generator produced no likely misspellings for thirtieth, since its letter sequence doesn't invite the usual edit-distance slips. This entry stands alone in our confusable dataset, since no other headword is close enough in sound or shape to pair with it.
Etymologically, the entry records: From earlier thirteth, from Middle English thrittithe, threttiþe, thrittyde, from Old English þrītigoþa; equivalent to thirty + -eth. For the modern form, see the etymological notes at twentieth. The correct English form is thirtieth, spelled T-H-I-R-T-I-E-T-H.
Definition
- 1The ordinal form of the number thirty.
Etymology
From earlier thirteth, from Middle English thrittithe, threttiþe, thrittyde, from Old English þrītigoþa; equivalent to thirty + -eth. For the modern form, see the etymological notes at twentieth.
Synonyms
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); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.
Frequently Asked Questions
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Using “thirtieth”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is T-H-I-R-T-I-E-T-H - every other letter order is a misspelling in standard orthography.
- Say it as /ˈθɜːti.əθ/ (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
Other uncommon English words near this 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.