The original question that came to my mind was "How many one-letter words are there in English language?". But of course, I did some research and found out there are three:

  • A – an indefinite article
  • I – the first person singular nominative pronoun
  • O – an interjection, used in the translation of the vocative case of Latin, commonly used in poetry


Wiktionary also mentions that every letter is a word (because large dictionaries list each letter as a single-letter word. Each such word is defined as a noun, denoting the letter with which it is spelled.) and adds that this blurs the use-mention distinction:

  • mentioning the letter:

"Psychology" starts with a 'p'.

  • using as a word:

"Psychology" starts with a p.

On the other hand, there are sources out there that list only "a, I, O" as one-letter words or even just "a" and "I".

For example, University of Notre Dame mentions only "a" and "I" in cryptography notes.

Letters being a word seems like a bit controversial. Wikipedia explains letter as below:

A letter is a grapheme (written character) in an alphabetic system of writing, such as the Greek alphabet and its descendants. Letters broadly denote phonemes in the spoken form of the language, although there is rarely a consistent exact correspondence between letters and phonemes.

Letters may be used as words. The words a (lower or uppercase) and I (always uppercase) are the most common English letter-words. Sometimes O is used for "Oh" in poetic situations. In extremely informal cases of writing (such as SMS language) individual letters may replace words, e.g. u may be used instead of "you" in English, when the letter is pronounced as a homophone of the word.

So the questions are:

  • How many one-letter words are there really?

    • Can we say that only "a" and "I" are one-letter words in the current vernacular? (Because "O" is considered archaic, though there are exceptions like our beloved "O Canada")

    • Are informal abbreviations considered as a word (like "u" for "you")?

    • Are letters words?

Bonus: https://www.wordnik.com/lists/single-letter-words

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    And X is often used as a term (noun?) designating either the unknown or as a place holder for other terms.
    – bib
    Commented Feb 4, 2015 at 19:01
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    What if Q from Star Trek took the L train to the T intersection of C and D streets because he had a map where an X marked that spot? Would he get an A for following directions? K. Commented Feb 4, 2015 at 19:10
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    @KevinWorkman: O, U! :)
    – ermanen
    Commented Feb 4, 2015 at 19:26
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    The meaning of "word" is context dependent as you hint at in your question as you refer to a cryptography text: unless decrypting a poem or archaic text, "O" is unlikely to appear in the plain text. A spy may well say "meet u at..." or even "Mr X says ...", however, so I'd disagree with the cryptography course and include all 1-letter "words" in my dictionary for attacking a cipher.
    – Chris H
    Commented Feb 4, 2015 at 20:07
  • This might help - One-Letter Words, a Dictionary: Merriam-Webster, move over! Until now, no English dictionary ever found the fun or the fascination in revealing the meanings of letters. "One-Letter Words, A Dictionary" illuminates the more than 800 surprising definitions associated with each letter in the English alphabet. For instance, Conley uncovers 69 different definitions for the letter X, the most versatile and printed letter in the English language. Using facts, figures, quotations, and etymologies, the author provides a complete and enjoyable understanding of the one-letter word./.
    – user66974
    Commented Feb 4, 2015 at 20:48

2 Answers 2


We could start by attempting to define what a word is, but of course that definition would be made up of words, and I'm sure no one here woke up today intending to disappear into their own navel on a question like this. So we might instead simply note that, of the 26 possible single-letter "words," only three of them have meanings that go beyond tautological references to the letters themselves, or to representations thereof ("I drove my T-top to the Y intersection..."), and decide for ourselves how significant that difference is.

For myself, I would consider "words" that by their nature always fail the use-mention test to be trivial, and probably not worthy of the word word except in certain rather specialized contexts.

  • 1
    This question is predicated on an agreed definition of 'word'. And thus has no meaningful answer until one exists. Commented Feb 4, 2015 at 19:41
  • All the letters of the Alphabet are names once capitalised. A name is a noun. A noun is a word.
    – Brad
    Commented Mar 19, 2021 at 5:36

In relation to the use of Letters as words in common use there are commonly thought to be only two or three. "A & I" O is but seldom used for Oh, but makes up, what most people consider the three "one letter words". The rest of the letters are not meaningful words therefore they are not words???

But! it is "The context" of a sentence, the way it is used, "That makes a word not meaningful", however, is it not, still a word? But we get ahead of ourselves. What is a word? Well, let's have a look at nouns.

Nouns; A noun is a word that represents a person, place, or thing. Everything we can see or talk about is represented by a word. That word is called a "noun." You might find it useful to think of a noun as a "naming word."

A is for apple; How would any of us, have learnt English, without the names of the letters of the Alphabet? So what is A? a symbol or a noun? By my own and that of the Cambridge English Dictionary, our definition is, it is a noun. And a noun is a word.

Furthermore, all the letters of the Alphabet are names once capitalised, so does that not by definition make them a word? and are not all of them useful as well as meaningful?

Ha! you say but we have already established that A is a word. Well then, let's take a consonant this time and see what we can find.

C is for Cat so when can C be meaningful as a solo act? The Cambridge English Dictionary has several definitions of its singular use as a noun.

C noun: the third letter of the English alphabet

C noun (MUSICAL NOTE): in Western music, the first note in the scale

C noun (MARK): a mark given for an exam, a course, or a piece of work.

There are also several abbreviations for "C", which the "Hertical Cambridgites" also term Nouns.

C: Celsius, temperature,

C: money, Cent,

C: 100, a Roman numeral,

C: Coulomb; Electricity

and our peers have already defined an abbreviation as a word. Did we not already include "O" into the magic trio for its abbreviation of Oh?

But alas maybe it can only be a word if it is used by a Laureate not an Engineer, Accountant or God forgive "the plebs".

But let us digress further. What is a word?

Word noun (LANGUAGE UNIT); a single unit of language that has meaning and can be spoken or written:

The pivot here is, being spoken or written. Therefore I would say there are more than 30 singular Letters and Symbols in common use as words if we included all the letters and commonly used symbols like +, -, @, =, etc. In fact, if we were to include the currency symbols we could more than double this count.

Ref CED "A"

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    I think if you edited this to be a little less shouty and better structured, you would get more upvotes. I upvoted it based on its contents, hoping this will encourage you to make such an edit.
    – Canned Man
    Commented Jun 27, 2021 at 12:39
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    @Canned Man; As requested
    – Brad
    Commented Aug 25, 2021 at 6:12
  • Excellent! I also notice you are using semicolons incorrectly. Semicolons are supercommas; colons are used to introduce clauses. E.g.: ‘And he spake: “Thou shalt eat cookies!” and they all jubilated.’ ‘There are numerous ways to sort green food: you have vegetables, such as carrots, cabbage and cucumber; fruits, such as apples, pears and oranges; and berries, such as lingonberries and blackberries.’ ‘Numerous units of measurements have been named after scientists. [introduce list] • C: Celsius or Coulomb. • K: Kelvin. • W: Watt’
    – Canned Man
    Commented Aug 26, 2021 at 18:27
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    @Canned Man Well let us hope for a better future. I have: removed the left leg of a "teddy bear biscuit" from beneath my RH shift key; put my proofreader on final notice, it is so hard to get good labour nowadays; chastised the ponytail gang. And he spake: “Thou shalt not eat cookies whilst playing Scribblenauts.” Then relented as four ginourmous brown eyes pierced my resolve.
    – Brad
    Commented Aug 27, 2021 at 0:40
  • This is a good and charming answer but I don't really know what makes you call O an abbreviation of oh, if anything oh is an extension of O. If we trust Wiktionary en.wiktionary.org/wiki/O#English O is "From Middle English O, o, from Old English o, from Latin o and Ancient Greek ὦ (ô, interjection). Featured prominently in William Tyndale's 1525 translation of the New Testament." Oh, saith Wiktionary, is from O
    – Au101
    Commented Jun 29, 2023 at 2:52

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