I was writing a text when I came to say 'a union', then it struck me that I need to change the 'a' to 'an'. But for some reason, 'an union' didn't sound right.

Why doesn't it work? Is it because its a mass noun, instead of a regular noun?

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    It's because although the word union starts with a vowel, the beginning U is pronounced with a Y sound, so you use "a". It's the same principle as "a uniform" or "a unicycle". On the flipside, you have words which start with consonants but are pronounced with vowel sounds (like honour) which use an instead of a. Mar 9, 2016 at 12:38
  • Actually i'd take uniform out of the Y sound list, as it's uniform with a strangely not Y sounding start.
    – Sakatox
    Mar 9, 2016 at 12:43
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    @Sakatox ~ how do you conclude that? OED says you are wrong: "Pronunciation: /ˈjuːnɪfɔːm/" Mar 9, 2016 at 12:47
  • Regional differences, although i did check and all official sources have it as you say. Either my ears deceived me, or i heard wrong before. Carry on. Actually, now that i think about it - say a uniform, and an uniform. Uniform works both ways, considering An uniform is congruent to undo in pronunciation, oh well, common usage is common usage.
    – Sakatox
    Mar 9, 2016 at 12:56
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2 Answers 2


The simplest way to explain this is to recognize that there are exceptions to every English rule, and that this is just... one of those.

The reason is that, as others have stated, the actual pronunciation of the initial syllable is 'yun,' which begins with 'y,' which in this case, is a consonant sound, as in 'you' (as opposed to ai / ee, its vowel sounds). The actual rule to remember is that it isn't the letter itself that matters - it's the pronunciation.

If the correct pronunciation of the word begins with a consonant sound, it should be preceded by 'a' instead of 'an.'

I'm struggling to find another example of this besides the 'y' / 'u' sound. I'm sure one exists - English is FULL of complicated loopholes like this.

  • But you = /juː/, it's because it doesn't start with a vowel sound, it's because of the j.
    – Schwale
    Mar 9, 2016 at 18:12
  • A hair, a hare, an heir.
    – gnasher729
    Mar 9, 2016 at 21:11

The general rule is as you pointed out, but there are certain words that have a non-vowel sounding start, or can behave differently depending on context.

There's the overall, commonly accepted pronunciation of words, so union goes with an a. You could've thought it didn't sound right, because it's too close to onion or somesuch. Depends on context - see the wiki article on mass nouns: A bit removed from the actual issue, still retains a bit of connection to it, though.

Consonant starts usually get an a article, an vowels usually get an as a article, sounding is a good rule of thumb. Then you have unions, and such.

  • "a/an" are articles, indefinite articles, and no prepositions.
    – rogermue
    Mar 9, 2016 at 13:41
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    This answer complicates things overly. The answer is simple: if it starts with a consonant or semi-vowel sound then use 'a'. If it starts with a vowel sound then use 'an'. Spelling is a complete irrelevance. "GIve me an F, a G an H and a U" is right, because the names of the letters F and H start with vowel sounds in English, but G and U don't.
    – Colin Fine
    Mar 9, 2016 at 17:20
  • @ColinFine: I know people who would disagree on the H. They say "haitch" and not "aitch".
    – gnasher729
    Mar 9, 2016 at 21:10
  • True. For them, it's "a H". Still simple.
    – Colin Fine
    Mar 9, 2016 at 23:52

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