Mac, Mc, or M' [Irish, = son], element in names derived from Irish and Scottish Gaelic patronymics. In most of these names the second element was a forename (e.g., Macdonald, in various spellings). Other names included titles or epithets (e.g., McIntosh [son of the chief]). Notions that some forms of the prefix are more typically Scottish or Irish are fallacious. Some of the names, however, have typical local distribution; thus, McLeod is Hebridean, McSweeney is especially Irish. See O; name.
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