I know the a/an rule, but as I meet both in my readings, I tried to google it, and I find both, with not site or dictionaries telling us we should use the one or the other one.

My question is: are they both common and accepted? Are they exceptions?

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    I don't know where you have found 'a undershirt', but it's incorrect. Words beginning with a vowel take 'an'. Commented Jan 12, 2020 at 17:43
  • 52
    For all practical purposes, the only thing that affects the a / an choice is whether the word starts with a vowel sound (it's irrelevant whether the written form starts with a "vowel" or "consonant" letter). Commented Jan 12, 2020 at 17:45
  • 5
    Related: “An hour” or “a hour”
    – Em.
    Commented Jan 13, 2020 at 2:42
  • 2
    @Tim Exactly. Well, almost.
    – JimmyJames
    Commented Jan 14, 2020 at 17:35
  • 2
    @Tim: an Ypres woman left an hour ago.
    – kthy
    Commented Jan 15, 2020 at 14:26

2 Answers 2


The correct article to use is an undershirt

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Google Ngram confirms

The American English term, undershirt, begins with a vowel sound
/ʌndərʃɜrt/ (Collins) and /ˈʌndəʃəːt/ (Lexico), and words beginning with a vowel sound take "an".

  • 4
    The pronunciation you have given at the end appears to be a British English pronunciation, not American English. Commented Jan 13, 2020 at 5:03
  • 1
    @EricWofsey lexico.com/definition/undershirt but some American speakers pronounce the letter r, aka as rhotic /r/ in "under" collinsdictionary.com/us/dictionary/english/undershirt. This has no influencer over the indefinite article.
    – Mari-Lou A
    Commented Jan 13, 2020 at 9:42
  • 5
    Some American dialects are non-rhotic but the "standard" and most common American prounciation is rhotic. Your first dictionary appears to exclusively display RP pronunciations and thus is not a source of information about American English pronunciation. Of course you are right that this is irrelevant to the indefinite article, I just worry that some learners may get confused by your last sentence and think that you are giving the standard American English pronunciation. Commented Jan 13, 2020 at 14:07
  • 1
    @RonJohn yeah, but unless you're secretly from Boston, you probably pronounce the "ir" part of the word with an actual "r" sound, and not just with the vowel in "eugh" on its own, as in non-rhotic dialects...
    – Muzer
    Commented Jan 14, 2020 at 10:47
  • 2
    @Muzer I noticed during a press conference about the Boston Marathon bomb incident that Bostonians save up the "r"s they remove from those words and add some of them to words like "law" in "law enforcement" (lawr enfahcement?), sort of like how Brits might refer to "Americer". There must be some kind of Conservation of R Law(r) at work here. Commented Jan 14, 2020 at 23:30

My favorite example is

An uninformed man
A uniformed man (a you-knee-formed man).

You use an if the next word sounds like it starts with a vowel, a if the next word sounds like it starts with a consonant.

There are cases where there is no universal agreement about pronunciation. Some people say "a hotel" (a hoe-tell), some say "an hotel" (an oh-tell).

When abbreviations are written down, some people will read them aloud as the letters in the abbreviation, and some will read them aloud as words. NDA is read as "en-dee-aye" or "non-disclosure agreement"; you use an or a depending on how you read it.

  • 56
    Even better is "a unionised workforce" vs "an unionised gas" (-ized if you prefer)
    – AakashM
    Commented Jan 13, 2020 at 10:49
  • 14
    ("a you-nyan-ized workforce" vs "an un-eye-oh-nized gas") Commented Jan 13, 2020 at 15:51
  • 6
    @AakashM Oh man it took me a while to figure out you meant un-ionised gas
    – slebetman
    Commented Jan 14, 2020 at 1:53
  • 1
    "A unicorn let the maiden pet it."
    – RonJohn
    Commented Jan 14, 2020 at 3:29
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    – ColleenV
    Commented Jan 17, 2020 at 11:03

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