Posted by Smokey Stover on May 23, 2007
In Reply to: Sorry, Mac posted by MK on May 23, 2007
: Sorry, Mac.
: What is the origin of the phrase?
The plain English meaning is, "I'm sorry, fella." The words Mac, fella, pal, chum, are ways of saying, either in a friendly manner or not, "You, Whatever-your-name-is." The Oxford English Dictionary says "[Mac:]Used as a familiar form of address to a (male) stranger", and other dictionaries say the same thing in different words.
My guess (an easy one) is that it started someplace where men of Irish or Scottish extraction were commonly encountered.