In the world of English spelling, there are few words as consistently frustrating as the ordinal form of the number nine. You know how to spell nine, and you certainly know how to spell ninety and nineteen. So, naturally, your brain wants to add that “e” and type nineth.
But here is the hard truth: Nineth is a misspelling.
To rank your writing at the top—and to avoid a red underline from every spellchecker on the planet—you must master the curious case of the disappearing “e.” This guide explains why the rule exists, how to remember it, and how to avoid similar traps.
Table of Contents
1. The Quick Answer: One Correct Way
There is no regional debate here. Whether you are in New York, London, or Sydney, there is only one accepted spelling:
- Correct: Ninth
- Incorrect: Nineth
Unlike center vs. centre or practice vs. practise, ninth is a universal standard. If you include the “e,” it is considered a functional error in all professional, academic, and legal contexts.
2. Why the “E” Disappears: The Rule of Exceptions
Most English words ending in a silent e keep that letter when you add a suffix starting with a consonant.
- Hope + ful = Hopeful
- Safe + ty = Safety
However, ninth is part of a small group of “rule-breakers.” When adding the suffix -th to nine, we drop the silent e. This happens for a few reasons:
Phonetic Clarity
If we kept the “e” (nineth), it might suggest a two-syllable pronunciation like “nine-eth.” By dropping the “e,” we clarify that the word is a single, crisp syllable: /naɪnθ/.
Historical Evolution
In Old and Middle English, several spellings competed for dominance. By the time modern English standards were solidified, the version without the “e” won out simply because it was more efficient and reflected the common pronunciation.
3. The “9-Family” Comparison
The most confusing part about ninth is that it doesn’t match its siblings. This is the primary reason people make the mistake.
| Number | Base Word | Suffix | Final Spelling |
| 9 | Nine | N/A | Nine |
| 19 | Nine | -teen | Nineteen (Keep the E) |
| 90 | Nine | -ty | Ninety (Keep the E) |
| 9th | Nine | -th | Ninth (Drop the E) |
4. How to Remember: The “Ninth is a Thief” Trick
If you struggle to remember this, use this simple mnemonic:
“The Ninth letter is a thief; it stole the ‘e’ from the nine.”
Alternatively, think of other ordinal exceptions. You don’t say “fiveth,” you say fifth. Just as “five” changes its internal structure, “nine” loses its tail.
5. Other Words That Drop the “E”
You aren’t just memorizing one word; you’re learning a pattern. Ninth belongs to a specific club of words that drop the silent e before a consonant suffix:
- Argue + -ment = Argument (Not arguement)
- True + -ly = Truly (Not truely)
- Due + -ly = Duly (Not duely)
- Whole + -ly = Wholly (Not wholely)
6. Usage in Different Contexts
Despite the spelling, the usage remains straightforward.
- Ordinal Position: “She finished in ninth place.”
- Fractions: “A ninth of the pie was missing.”
- Music: “The composer is famous for his Ninth Symphony.”
- Dates: “The meeting is scheduled for the ninth of May.”
Summary Checklist
- Is there an “e”? If yes, delete it.
- Does it look weird? Yes, “ninth” looks a bit naked without the “e,” but that means it’s correct.
- Are you writing 90? Keep the “e” for ninety.
- Are you writing 9th? Use ninth.
FAQ: Ninth or Nineth?
Is “nineth” correct in British English?
No. It is a common misconception, but “ninth” is the only correct spelling in both American and British English.
Why does “ninety” keep the “e” but “ninth” doesn’t?
“Ninety” requires the “e” to separate the “n” and the “t” to maintain its two-syllable sound. In “ninth,” the “th” blends directly with the “n” sound, making the “e” unnecessary.
What about 19th?
For 19th, you actually keep the “e”: Nineteenth. The exception only applies to the single digit 9.
