My daughters asked me what the Mc, Mac, and O' beginnings of names are called. Is there a specific name for that specific part of a surname?

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    It's a form of patronymic prefix. Patronymics refer to a father's name, like Russian Ivanovich, meaning 'son of Ivan' or Icelandic Janadottir for 'daughter of Jan'. May 16, 2015 at 16:24
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    @JohnLawler Why not make this an answer? It's better than the other options. Jul 15, 2015 at 20:17

2 Answers 2


It's called a prefix, just like for other words. See this question for some more detail and explanations of what some common prefixes mean: Etymology for “Mc‑” and “O’‑” prefix in surnames


It's known either as simply a prefix, or, more technically, a nobiliary particle. (As always, Wikipedia weighs in as well.)

  • How are Mac and O’ “nobiliary”? Even the Wikipedia article you give a link to disagrees: “In Scotland, there is strictly no nobiliary particle.” Apr 13, 2018 at 15:15

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