Nineth or Ninth: Which Spelling Is Correct for the 9th?

Many people stop and wonder about nineth or ninth when they write a date, a grade or a ranking. The two spellings look close, but only one is right. This article gives a clear answer and shows how to use it.

You will see the correct spelling, the reason the “e” disappears and examples you can copy. You will also learn how to spell larger numbers that end in nine, such as twenty-ninth and ninety-ninth.

Quick Answer

Ninth is the correct spelling. Nineth is a misspelling. Write “ninth” any time you spell out the ordinal number that comes after eighth and before tenth.

Nineth vs Ninth at a Glance

Context	Correct form	Example	How to tell
Position in a series	ninth	She finished ninth.	Drop the “e” from nine
Date	ninth	We meet on the ninth.	Same spelling in speech and writing
Fraction	ninth	A ninth of the cake	One of nine equal parts
Compound number	twenty-ninth	The twenty-ninth floor	Spell the last part as “ninth”
Misspelling	nineth	Not correct	Never use this form

All examples in the table are illustrations written for this article.

Nineth or Ninth: Why the E Drops

Most ordinal numbers add “th” to the cardinal number. Four becomes fourth. Six becomes sixth. Ten becomes tenth.

A few numbers change a little before “th”. Five becomes fifth and twelve becomes twelfth. Nine joins this group because it loses its final “e”. The result is ninth.

This is the whole rule. If you write “nine” and add “th”, you get “nineth”, which is wrong. Remove the “e” first.

Do not confuse this with ninety. Ninety becomes ninetieth, and nineteen becomes nineteenth. Those words keep their endings, so the “e” stays only in those longer forms.

What Ninth Means

Ninth has a few uses. Each one follows the same spelling. The dictionary entry at Merriam-Webster lists the main senses.

Ninth as a Position

The most common meaning is the one that is number nine in a series. You can use it as a noun, an adjective or an adverb.

Here are some examples:

• The ninth day of the month (adjective)
• The book’s ninth edition (adjective)
• He finished ninth in the race (adverb)
• The batter hit a home run in the bottom of the ninth (noun)

Ninth as a Fraction

Ninth can also mean one of nine equal parts of something. For example, “She owned a ninth of the company.” The plural is ninths, as in “three ninths of the pie.”

Ninth in Music

In music, a ninth is an interval that covers an octave and a second. It can also name the tone at that interval or a chord that contains it. Musicians use the same spelling, so “ninth chord” never has an “e” in it.

How to Spell Ninth in Compound Numbers

Compound ordinals follow the same rule. Spell the last word as “ninth” and keep the earlier words in their usual form.

• Nineteenth stays as it is because it follows a different pattern
• Twenty-ninth
• Thirty-ninth
• Ninety-ninth
• One hundred and ninth

Notice that the ordinal ending only applies to the final word. You write “twenty-ninth”, not “twentieth-ninth”.

Common Mistakes With Ninth

The most common error is writing “nineth”. Spell checkers usually flag it, but a fast typist can miss the red line.

Some writers also mix up the forms of nine. “Nines” is the plural of nine, as in “dressed to the nines”. “Ninths” is the plural of ninth. They are different words with different meanings.

A third mistake is adding extra letters when you write the number in numerals. The short form is “9th” with no space and no extra letters. Both “9th” and “ninth” are fine, but style guides often prefer words for small numbers in formal text.

Easy Ways to Remember the Spelling

Try one of these quick tricks:

1. Nine loses its “e” when “th” arrives.
2. Say “nine plus th” in your head, then cross out the “e”.
3. Remember that fifth also drops a letter, so ninth fits a pattern you already know.

If you still feel unsure, type the number as “9th” and check it against your style guide.

Conclusion

The nineth or ninth question has a simple answer. Ninth is correct and nineth is not. Nine loses its final “e” before the “th” ending, just as five becomes fifth and twelve becomes twelfth.

Use the same spelling in every context. It works for a place in a race, a day of the month and a school grade. It also works for a fraction, a musical interval and any compound number such as twenty-ninth or ninety-ninth.

Keep one small memory trick in mind. Think “nine minus e plus th” each time you write the word. If you are working fast, run a quick spell check before you publish, because a typing slip can turn “ninth” into “nineth” without you noticing.

Finally, remember that “9th” is also fine in many cases. Style guides differ on when to use numerals and when to use words, so follow the guide your school, publisher or employer uses. Whichever form you choose, the spelling in words stays the same: ninth.

FAQ

Is nineth ever correct?

No. Nineth is a misspelling of ninth, and no standard dictionary spelling uses it. Merriam-Webster lists only “ninth” for the ordinal that follows eighth.

How do you spell 9th in words?

Spell 9th as “ninth”. Take the number nine, drop the final “e” and add “th”. You can use the same word for a date, a grade or a place in a race.

How do you spell 29th in words?

Write it as “twenty-ninth”. Put a hyphen between the two parts and spell the last part as “ninth”. The same pattern gives you thirty-ninth and ninety-ninth.

What is the plural of ninth?

The plural is “ninths”. You use it mostly for fractions, such as “two ninths of the total”. Do not confuse it with “nines”, which is the plural of the number nine.