thirtieth: meaning, definition, pronunciation and examples
B1Neutral - used across formal, informal, and technical contexts.
Quick answer
What does “thirtieth” mean?
The ordinal number corresponding to thirty.
Audio
Pronunciation
Definition
Meaning and Definition
The ordinal number corresponding to thirty; the position of thirty in a series.
Denoting one of thirty equal parts (1/30).
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. The spelling is identical. Pronunciation differences follow general US/UK patterns for 'th' and vowel sounds.
Connotations
Neutral in both variants. Can carry connotations of a milestone or a specific point in a sequence (e.g., a thirtieth anniversary).
Frequency
Equally common in both varieties, with frequency tied to the context of enumeration and fractions.
Grammar
How to Use “thirtieth” in a Sentence
the + thirtieth + noun (the thirtieth applicant)be + the + thirtieth + to-infinitive (She was the thirtieth to cross the line)ordinal + in + series (the thirtieth in a long line of successors)Vocabulary
Collocations
Examples
Examples of “thirtieth” in a Sentence
adjective
British English
- They celebrated their thirtieth wedding anniversary with a trip to the Lake District.
- The thirtieth chapter of the novel was particularly suspenseful.
- He finished in thirtieth position in the marathon.
American English
- Their thirtieth anniversary party is at the community center.
- Please turn to the thirtieth page in your manual.
- She was the thirtieth person to sign up for the workshop.
Usage
Meaning in Context
Business
Refers to dates, payment schedules (e.g., 'net 30th'), or rankings.
Academic
Used in historical sequencing, statistical percentiles, or fractional division.
Everyday
Common for birthdays, anniversaries, and dates.
Technical
Used in mathematics for fractions (one-thirtieth) and in ordered lists.
Watch out
Common Mistakes When Using “thirtieth”
- Spelling: 'thirtyth' (incorrect), 'thirtieth' (correct). Pronunciation: Omitting the second 't' sound (/ˈθɜː.ti.əθ/ not /ˈθɜː.ti.ə/). Using as cardinal: 'I have thirtieth books' (incorrect) vs 'I have thirty books' (correct).
FAQ
Frequently Asked Questions
You write it as 'thirtieth'.
It can function as both. As an adjective: 'the thirtieth day'. As a noun: 'She finished in thirtieth.'
For numbers ending in '-ty' (like twenty, thirty, forty), you change the 'y' to 'i' and add '-eth' (e.g., twentieth, thirtieth, fortieth).
The first 'th' is voiceless /θ/ as in 'think'. The 'th' at the end is also voiceless /θ/. In American English, the 't' in the middle may be pronounced as a flap /t̬/.
The ordinal number corresponding to thirty.
Thirtieth is usually neutral - used across formal, informal, and technical contexts. in register.
Phrases
Idioms & Phrases
- “the thirtieth of never (humorous: a time that will never come)”
Learning
Memory Aids
Mnemonic
Think of 'thirty' and just add '-eth' like 'twentieth' or 'fiftieth'. Remember the 'y' changes to 'i' before adding '-eth' (thirty -> thirtieth).
Conceptual Metaphor
A POINT ON A PATH (the thirtieth step on a journey), A SLICE OF A WHOLE (one-thirtieth of the pie).
Practice
Quiz
What is the correct fractional form?