‘20th Century’ or ‘20rd Century': Which is Correct?

By Amy Gilmore, updated on December 12, 2023

Are you curious about whether '20th century' or '20rd century' is correct? This guide will help!

Here is an overview, in case you are in a rush:

  • '20th century' is correct because '20th' is the correct numeric abbreviation of the ordinal twentieth.
  • '20rd century' is a grammatical error that you should never use.

The short answer above will help if you need to quickly determine which of these terms to use. However, there is a lot more to learn. Sticking around until the end of the lesson will help you learn how to abbreviate other ordinals and help you remember the correct spelling of '20th century.'

'20th Century' or '20rd Century': Which is Correct?

When it comes to whether to use '20th century' or '20rd century,' you should always use the former. The latter is always a grammatical error. So, you should avoid using it.

The term '20th century' is a reference to a specific time period in a series of centuries. Therefore, you use the ordinal form.

What are Ordinals?

Ordinals are numbers that are ranked or appear in a series or group of other ranked items or individuals. The opposite of an ordinal is a cardinal number. Cardinal numbers are not associated with position or rank.

Examples of cardinal numbers include:

  • One - 1
  • Two - 2
  • Three - 3
  • Thirteen - 13
  • Twenty - 20
  • Forty-five - 45
  • Sixty-two - 62
  • Eighty-four - 84
  • One hundred sixteen - 116
  • Two-hundred-forty-three - 243

Examples of ordinal numbers include:

  • One - First/1st
  • Two - Second/2nd
  • Three - Third/3rd
  • Thirteen - Thirteenth/13th
  • Twenty - Twentieth/20th
  • Forty-five - Forty-fifth/45th
  • Sixty-two - Sixty Second/ 62nd
  • Eighty-four - Eighty-Fourth/84th
  • One-hundred-sixteen - One hundred sixteenth/116th
  • Two-hundred-forty-three - Two hundred forty-third/243rd

How to Create Ordinals

You create ordinals by adding an st, rd, or th suffix to the end of the written number, for example:

  • One - First or 1st
  • Two - Second or 2nd 
  • Three - Third or 3rd
  • Four - Fourth or 4th
  • Five - Fifth or 5th
  • Six - Sixth or 6th
  • Seven - Seventh or 7th
  • Eight - Eighth or 8th
  • Nine - Nineth or 9th
  • Ten - Tenth or 10th
  • Twenty - Twentieth or 20th
  • Thirty - Thirtieth or 30th 
  • Forty - Fortieth or 40th

As you can see, the suffix after the numeric value always matches the suffix used to create the word format of the ordinal.

Definition of '20th Century': What Does '20th Century' Mean?

The Merriam-Webster Dictionary does not list a definition for '20th century.' So, we are going to look at the definitions of '20th' and 'century.'

Definition of '20th'

'20th' is a noun that means:

  • One that is number 20 in a series
  • One of twenty equal parts of something

'20th' can also be an adjective used to describe a noun or an adverb to describe a verb, for example:

  • 20th examination
  • 20th person
  • 20th vehicle
  • 20th parking spot
  • 20th year
  • 20th anniversary
  • 20th attempt
  • 20th century
  • 20th day
  • 20th violation

Pronunciation: How to Pronounce '20th' Century

Pronunciation is another important aspect of learning a new language or word. If you incorrectly pronounce terms, other people will not understand you. Therefore, it is vital to learn the correct way to say words, especially if you are communicating verbally or speaking in front of a crowd.

So, here is a pronunciation guide for '20th century.'

  • Use this phonetic spelling to pronounce '20th century':


Tips for When and How to Use '20th Century'

The order of numbers and the way ordinals are typically used may be confusing when you are using them to describe centuries. So, here are some tips.

  • The '20th century' covers the years 1901 through 2000.

So, you might write:

People born in the 20th century are between 23 and 123 years old. 

  • Use '20th century' to describe something that took place during the 1900s

As an example, you could say:

My mom's birthday is June 3rd, 1986. She was the last person in our family to be born in the 20th century.


The Great Depression was a significant event during the 20th century. 

  • Use '20th century' in place of 1900s.

For example, you might say:

From what I've seen from the first two decades of the 21st century, I wish we could go back to the 20th century.

Sample Sentences Using '20th Century'

Before you leave, read these sample sentences using '20th century.' They will teach you ways to use the term in additional contexts and help you remember the correct spelling.

20th Century

  • Do you wish that you could go back to the 20th century or visit another century?
  • Living in a house built in the early 20th century is interesting.
  • There were two world wars during the 20th century that still cause tension amongst nations today.
  • The first world war of the 20th century was called the Great War.
  • If you were born during the 20th century, you might remember a time when people did not have cell phones.
  • What was your favorite movie from the 20th century? Mine were The Wizard of Oz and Charlie and the Chocolate Factory.
  • The 20th century was a time of great development for society in the United States and around the world.
  • I am happy that I was born during the 20th century when life seemed slower and simpler.
  • Kids born after the 20th century will never know what it was like to live without a phone or mobile device connecting them to responsibilities and expectations.

Review of Whether '20th Century' or '20rd Century' is Correct

We reviewed a lot of information. So, here is a quick recap of whether you should use '20th century' or '20rd century':

  • '20th century' is the correct ordinal term for the century covering 1900 through 2000. 
  • '20rd century' is a grammatical error because the correct spelling of the ordinal for 20 is twentieth or 20th

Ordinals are challenging for many people, especially people learning English as a second language. It is hard enough to learn a whole new set of terms for all of the numbers.

When you create ordinals, the spellings change significantly in many cases, and the pronunciations can be difficult, too. So, if you need help learning about other ordinals and commonly misspelled and misused English terms, check out the other guides in the confusing words section here.

Each contains valuable information about the terms it covers, including definitions, usage tips, grammar rules, examples, and pronunciations. So, be sure to check them out.

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Written By:
Amy Gilmore
Amy Gilmore is one of the lead freelance writers for WritingTips.org. She has been a professional writer and editor for the past eight years. She developed a love of language arts and literature in school and decided to become a professional freelance writer after a demanding career in real estate. Amy is constantly learning to become a better writer and loves sharing tips with other writers who want to do the same.

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