thirtieth

/ˈθɜːti.əθ/

//ˈθɜːti.əθ// adj

"thirtieth" is a 9-letter English headword indexed on PlainSpell.

The verdict

“thirtieth” is uncommon English (frequency #54,533 among 3,151 “T” headwords), classed as an adjective. The kind of spelling people second-guess.

#54,533
frequency rank, English
3,151
“T” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The ordinal form of the number thirty.

Corpus desk

Index EN-thirtieth · thirtieth · English

thirtieth · rank #54,533 · 0 variants · 0 confusables

  • FREQ-RARE #54,533
  • LEN-LONG 9 letters
  • VOW-3 3 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 3,151
  • PHOTO-FINISH torr

Nearest frequency peer: torr (+2 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.

Long-tail ranks near “thirtieth”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “thirtieth” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for thirtieth
PropertyValue
Headwordthirtieth
LanguageEnglish
Part of speechAdjective
IPA/ˈθɜːti.əθ/
Letters9
Frequency rank#54,533
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “thirtieth” in English

Word frequency stretches from the small set of words we reach for constantly (left) out to the long tail barely used once in a while (right).thirtiethfalls in this rarity band:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Rare peers in the same band: “torr” (#54,535), “tew” (#54,530), “tetracycline” (#54,529). Among 3,151 “T” headwords, “thirtieth” is #54,533. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

thirtieth is uncommon English at frequency #54,533 among 3,151 “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

  1. 1
    The 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

How do you spell "thirtieth"?
"thirtieth" is spelled T-H-I-R-T-I-E-T-H. The IPA pronunciation is /ˈθɜːti.əθ/.
What does "thirtieth" mean?
As an adjective, "thirtieth" means: The ordinal form of the number thirty.
How do you pronounce "thirtieth"?
The IPA (International Phonetic Alphabet) transcription for "thirtieth" is /ˈθɜːti.əθ/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "thirtieth"?
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. See the full etymology section above for more details.
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.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "thirtieth", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 9 letters (nearest by frequency rank).

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

Source: FrequencyWords open word-frequency list