# McLastname and MacLastname question

**URL:** <https://boards.straightdope.com/t/mclastname-and-maclastname-question/529803>\
**Category:** Factual Questions\
**Created:** [February 20, 2010, 8:37pm UTC](https://boards.straightdope.com/t/mclastname-and-maclastname-question/529803 "2010-02-20T20:37:22Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Enright3](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/enright3/32/2897_2.png) [@Enright3](https://boards.straightdope.com/u/Enright3)\
**Post date:** [February 20, 2010, 8:37pm UTC](https://boards.straightdope.com/t/mclastname-and-maclastname-question/529803/1 "2010-02-20T20:37:22Z")

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In the movie A River Runs Through It the family is having a conversation about how so-and-so MacLain started capitalizing the ‘L’ in their last name and now he’s going to look like one of those low land Scots.

Ok the general question is: was this really considered an indication? Next question is what’s the difference between Mc and Mac? I’ve heard varies things like Mc is Irish and Mac is Scotish. I’ve also heard that Mc is a prefix that essentially means ‘son-of.’

If we tackle this we’ll move on to the etymology of o  
O’Lastname. 🙂

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**Author:** ![fubbleskag](https://avatars.discourse-cdn.com/v4/letter/f/c2a13f/32.png) [@fubbleskag](https://boards.straightdope.com/u/fubbleskag)\
**Post date:** [February 20, 2010, 8:47pm UTC](https://boards.straightdope.com/t/mclastname-and-maclastname-question/529803/2 "2010-02-20T20:47:46Z")

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My (admittedly limited) understanding is as follows:

Mac = Son of  
Mc = an abbreviation of Mac  
O’ = Grandson of

(no comment on the significance of capitalization as outlined in the referenced movie)

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**Author:** ![Slithy\_Tove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slithy_tove/32/18248_2.png) [@Slithy\_Tove](https://boards.straightdope.com/u/Slithy_Tove)\
**Post date:** [February 20, 2010, 8:58pm UTC](https://boards.straightdope.com/t/mclastname-and-maclastname-question/529803/3 "2010-02-20T20:58:58Z")

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It get’s interesting when the Celts & the Vikings intermarried: The teacher who was killed on the Challenger or the general who said "nuts’ at the Battle of the Bulge would be remembered as “Olafson” if their ancestors had stayed in Norway, but instead became McAuliffes.

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [February 20, 2010, 9:01pm UTC](https://boards.straightdope.com/t/mclastname-and-maclastname-question/529803/4 "2010-02-20T21:01:25Z")

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O’ is almost always Irish, while Mac or Mc is usually Scottish. Most Irish with Mac names are Scots-Irish, descendants of Protestant Scots that the English encouraged to move to the isle to displace the Catholic Irish.

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**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\
**Post date:** [February 20, 2010, 9:32pm UTC](https://boards.straightdope.com/t/mclastname-and-maclastname-question/529803/5 "2010-02-20T21:32:21Z")

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Keep in mind that whether it’s Mc or Mac now, it was likely just M’ back in the old days, as in M’Henry and M’Naughton. Plus, spelling was not standardized back then, so expecting people to settle on Mc or Mac consistently is anachronistic.

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**Author:** ![toodlepip](https://avatars.discourse-cdn.com/v4/letter/t/97f17d/32.png) [@toodlepip](https://boards.straightdope.com/u/toodlepip)\
**Post date:** [February 20, 2010, 10:49pm UTC](https://boards.straightdope.com/t/mclastname-and-maclastname-question/529803/6 "2010-02-20T22:49:18Z")

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O’ is considered exclusively Irish, it originally meant “grandson of”. Mac/Mc, “son of”, is found in both Scottish and Irish surnames. Both have come to mean “descendant of”, since true patronyms aren’t in use.

It’s worth noting that although Mc is an abbreviation of Mac (or Mhic), the two are no longer interchangeable, no more than any other spelling variations are interchangeable. For instance, McRae, MacRae, McCrae, MacRay and many other versions are the same name, pronounced the same way, but family branches settled on different standardised spellings.

Around one in eight Scots have a surname prefixed with Mac or Mc. The percentage is much higher in the Highlands and Western Isles. In these areas, Mac is almost exclusively the spelling of choice, and Mc is thought of as the Lowland spelling.