Mc (or Mac) is often used as a prefix in Gaelic-derived names.

In one class containing most such names, prefixing Mc does not affect the position of the accent somewhere on the base name. Thus Mc is unstressed. For example:

  • McDonald /mɛkˈdɑnl̩d/
  • MacArthur /mɛkˈarθr̩/
  • McCoy /mɛk̚ˈkoj/
  • McGill /mɛˈɡɪl/
  • McMahon /mɛkˈmæn/
  • McCarthy
  • McLeod
  • McDonnell
  • McCormack
  • McEwan
  • McAllister
  • McOrmond
  • McNuggets

But sometimes Mc takes stress:

  • McIntosh /ˈmækɪntɑʃ/
  • McIntyre /ˈmækɪntajr̩/
  • McAfee /ˈmækəfi/
  • McAvoy /ˈmækəvoj/

All of these I could think of contain a vowel-initial base name, but that's not a sufficient condition.

How can you determine which class a particular name belongs to, and what is the etymological reason for the distinction?

  • I would argue that the stress is on the Mac part of MacArthur, or at least that Mac and Ar have almost equal stress. Note that the base name of your stressed examples start with vowel -- this might be the difference. Commented Jul 9, 2012 at 3:01
  • 2
    @cornbreadninja: 'McIntosh' is the only one for me that has the stress on the 'mc'. (even though I realize that many stress 'McAfee' on the first, that neer sounds natural to me (as a plain old AmE speaker)).
    – Mitch
    Commented Jul 9, 2012 at 3:21
  • @cornbreadninja: But that's not a sufficient condition for being in the stressed class. Commented Jul 9, 2012 at 4:22
  • 5
    Proper names are not subject to general constraints on stress, in the first place, and prefixes from other languages are even less so. There's no regularity here to express with rules. Commented Jul 9, 2012 at 4:45
  • @Mechanicalsnail that is why I said might, and commented rather than answered. Commented Jul 9, 2012 at 15:39

2 Answers 2


Check this: John Wells’s phonetic blog, "Joe Mc-what?"

the prefix M(a)c- means ‘son of’ in Irish and Scottish Gaelic. The general rule is that

  • before a stressed syllable it is pronounced mək, or in a more formal style perhaps mæk; thus McBride, McDonald, McEwan, McPherson
  • before an unstressed syllable it is mæk, and is itself stressed; thus McAnulty ˌmækəˈnʌlti, McAvoy ˈmækəvɔɪ, McEnroe, McIntosh, McNamara
  • but before k or g it is reduced to , thus McCarthy məˈkɑː(r)θi, McCorquodale, McGill, McGonagall, McQueen.

The problem with McElderry, and with several other names of three or more syllables, is knowing whether the second syllable is stressed or not.

There is more information in the blog post and the comments below.


I believe it's just a case of a family name being pronounced as a family prefers to pronounce it, as well as the tendency to slur or shorten common words (such as m'lady for "my lady"), but there is one interesting aspect of Gaelic designations that may apply.

In Gaelic, Mac means "son" or "son of" and is pronounced Mack (as the "Mc" in McIntosh.) Mhic means "wife of the son of" and is pronounced as the "Mc" in McCoy. A woman with the given name of Niamh who married a man named Colm Mac Intosh would then be known as Niamh Mhic Intosh.

  • I've heard that 'mhic' was also for grandfather (like "O'").
    – Mitch
    Commented Jul 9, 2012 at 17:12
  • Been a while since I was in Ireland, but if I remember correctly, Mac = Son of, O'= grandson (or great-grandson, or great-great etc), Bean Mhic (shortned to Mhic) = wife of the son of and Nic = unmarried daughter of. I think there's a feminine version of O' as well, but I don't remember what it is.
    – Marcus_33
    Commented Jul 9, 2012 at 17:24

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