# 21St Or 21Th

When it comes to writing about and discussing dates, the question of whether to use “21st” or “21th” is one that often arises. In this article, we’ll explore the correct usage of these two terms and provide some tips for ensuring your writing is clear and concise.

So, let’s start with the basics. When we refer to a specific day in English, we typically use an ordinal number – that is, a number that indicates a position or order in a sequence. For example, we might say “the 1st of January” to refer to the first day of the year.

When it comes to writing the ordinal number for the 21st day of the month, however, there seems to be some confusion. Some people write “21st”, while others insist that “21th” is the correct form. So, which is it?

The answer is simple: “21st” is the correct form. There is no such thing as “21th” – at least, not in standard English usage. The suffix “-st” is used for all ordinal numbers ending in “1”, including “21st”, “31st”, and so on.

Now that we’ve cleared up that confusion, let’s look at some other tips for using ordinal numbers correctly in your writing.

1. Use ordinal numbers to describe dates.

As we’ve already mentioned, ordinal numbers are used to indicate a position or order in a sequence. When we’re talking about dates, this means that we use ordinal numbers to describe the specific day of the month.

For example, instead of writing “January 1”, we would write “January 1st”. Similarly, we would write “December 25th” instead of “December 25”.

2. Pay attention to capitalization.

In English, ordinal numbers are typically written with superscript letters (“st”, “nd”, “rd”, or “th”) and lowercase letters. For example, we write “21st” or “31st”, not “21ST” or “31ST”.

It’s also worth noting that ordinal numbers are not capitalized when they appear in the middle of a sentence. For example, we might write “I was born on the 3rd of March” but “March 3rd was a significant day in my life”.

3. Be consistent.

Consistency is key when it comes to using ordinal numbers. If you’re writing a document or article that includes multiple dates, make sure that you use the same format for all of them.

For example, if you choose to use the abbreviated form (“1st” instead of “first”), make sure that you use this form consistently throughout the document. Don’t switch back and forth between different formats or your writing will become confusing and difficult to follow.

4. Watch out for irregular forms.

While most ordinal numbers follow a predictable pattern (adding “-st”, “-nd”, “-rd”, or “-th” to the end of the number), there are a few irregular forms that you should be aware of.

For example, the ordinal form of “11” is “11th”, not “11st”. Similarly, “12” becomes “12th” and “13” becomes “13th”. Make sure you know these irregular forms so that you can use them correctly in your writing.

5. Use ordinal numbers in addresses, too.

Ordinal numbers aren’t just used to describe dates – they can also be used to indicate a specific house number within a street or avenue. For example, “123 Main Street” might be written as “123rd Main Street” in some contexts.

If you’re writing an address that includes an ordinal number, make sure that you use the correct form (“23rd”, not “23th”) and that you follow any local conventions or customs that might apply.

In conclusion, the correct form for the ordinal number associated with the 21st day of the month is “21st”. Using “21th” would be incorrect and could lead to confusion or misunderstandings. By following the tips outlined in this article, you can ensure that your writing is clear, concise, and accurate when it comes to the use of ordinal numbers.