31th vs. 31st – Which is Correct?
The correct ordinal number is 31st. The form “31th” is an incorrect spelling and a common error, often arising from confusion with other ordinal numbers that end in “th.” Always use “31st” when referring to the thirty-first position, day, or item.
31th or 31st – Which is Correct?
When referring to the ordinal number that follows 30th, only one form is grammatically correct in English: 31st. The spelling “31th” is a common misspelling and does not exist as a valid word in the English language. This error often occurs because most ordinal numbers (like fourth, fifth, sixth) end in “th,” leading to a mistaken generalization for numbers ending in “1.” However, for numbers ending in 1, 2, or 3, specific suffixes are used: “st” (for 1st, 21st, 31st), “nd” (for 2nd, 22nd, 32nd), and “rd” (for 3rd, 23rd, 33rd).
The Best Trick to Remember the Difference
The easiest trick to remember whether to use “31th” or “31st” is to focus on the last digit of the number. If the number ends in a ‘1’, like 1, 21, or 31, it takes the ‘st’ suffix, just like “first.” Think: “One always goes with ‘st’, as in ‘first’.”
- 1st (first)
- 21st (twenty-first)
- 31st (thirty-first)
This simple rule helps avoid confusion with numbers like 4th, 11th, or 20th, where the ‘th’ suffix is appropriate.
| Word | Part of Speech | Meaning | Example |
|---|---|---|---|
| 31st | Ordinal Adjective / Ordinal Number | Denoting the position of an item in a sequence, corresponding to the number thirty-one. | The 31st of December is New Year’s Eve. |
| 31th | Incorrect | Grammatically incorrect; a misspelling of “31st.” | Please do not write “The 31th day of the month.” |
How to Use 31st
The term “31st” is an ordinal number used to indicate position in a sequence or a specific date. It functions as both an adjective and a noun, maintaining a formal and standard tone. It’s crucial for precision in dates, rankings, and sequential listings.
Example 1: Her birthday falls on the 31st of March this year, which is a Sunday.
Example 2: The company announced its quarterly results on the 31st of May, exceeding expectations.
Example 3: He crossed the finish line in 31st place, a personal best for the marathon.
What are the different forms of 31st?
“31st” is the standard abbreviated form of the ordinal number “thirty-first.” As an ordinal number, its form does not change based on tense or pluralization in the way verbs or nouns do. It consistently refers to the position corresponding to thirty-one. It can be written out as “thirty-first” or numerically as “31st.”
Etymology of the word 31st
The word “31st” derives from the combination of the cardinal number “thirty-one” and the ordinal suffix “-st.” The suffix “-st” is specifically used for ordinal numbers ending in “1” (e.g., first, twenty-first). The term “thirty” comes from Old English þrītig, meaning “three tens,” and “one” from Old English ān. The formation of ordinal numbers in English generally follows a pattern of adding “-th” to cardinal numbers, but “first,” “second,” and “third” (and compounds like “thirty-first”) are exceptions with unique suffixes based on their historical development from Old English roots.
Related Concepts
Understanding broader grammar concepts related to numbers and suffixes can help solidify the correct usage of “31st” and avoid common errors.
- Ordinal Numbers: These numbers indicate position or order in a sequence (e.g., first, second, third, thirty-first). They are distinct from cardinal numbers, which denote quantity (e.g., one, two, three, thirty-one).
- Ordinal Suffixes (-st, -nd, -rd, -th): English ordinal numbers use specific suffixes. Numbers ending in 1 (except 11) use “-st” (1st, 21st, 31st). Numbers ending in 2 (except 12) use “-nd” (2nd, 22nd). Numbers ending in 3 (except 13) use “-rd” (3rd, 23rd). All other numbers, including 11, 12, and 13, use “-th” (4th, 11th, 12th, 13th, 20th, 30th).
Examples from Media and Literature
- “The 31st of October is celebrated as Halloween in many Western countries.” – Common cultural reference.
- “In the novel, the protagonist’s journey began on the 31st day of spring, a symbolic new beginning.” – Fictional narrative.
- “The annual report highlighted that the company’s fiscal year ends on the 31st of December.” – Business news or financial reporting.
- “She was the 31st person in line, patiently waiting for the store to open.” – Everyday descriptive text.
- “The resolution was passed on the 31st vote, securing a narrow majority.” – Political or procedural context.
31st Synonyms
While “31st” specifically refers to the ordinal position, synonyms can describe the concept of being the final or latest in a sequence, or simply the numerical value when context allows.
| Synonym | Definition |
|---|---|
| Thirty-first | The full written form of the ordinal number. |
| Last (in a sequence of 31) | Referring to the final item when the total count is 31. |
| Final (in a sequence of 31) | Similar to “last,” emphasizing the conclusion of a sequence. |
Frequently Asked Questions
Question 1: Why is “31th” incorrect?
“31th” is incorrect because English ordinal numbers follow specific rules for suffixes. Numbers ending in ‘1’ (except 11) use the ‘st’ suffix, as in “first.” Therefore, the correct form is “31st.”
Question 2: What is the rule for forming ordinal numbers?
The general rule is: numbers ending in 1 use ‘st’ (1st, 21st, 31st); numbers ending in 2 use ‘nd’ (2nd, 22nd); numbers ending in 3 use ‘rd’ (3rd, 23rd). All other numbers, including 11, 12, and 13, use ‘th’.
Question 3: Can I write out “thirty-first” instead of “31st”?
Yes, “thirty-first” is the full written form of “31st” and is perfectly acceptable, especially in formal writing or when the number might appear at the beginning of a sentence. Both forms convey the same meaning.
Conclusion
In summary, the distinction between “31th” and “31st” is straightforward: “31st” is the only correct form for the ordinal number. “31th” is a common misspelling that should be avoided. Remembering that numbers ending in ‘1’ take the ‘st’ suffix, just like “first,” is the key to consistent and accurate usage. Mastering such specific grammatical details enhances clarity and reinforces your credibility as a precise communicator.
