from
Jargon File (4.4.4, 14 Aug 2003)
muggle
[from J.K. Rowling's Harry Potter books, 1998] A non-{wizard}. Not as
disparaging as {luser}; implies vague pity rather than contempt. In
the universe of Rowling's enormously (and deservedly) popular
children's series, muggles and wizards inhabit the same modern world,
but each group is ignorant of the commonplaces of the others'
existence -- most muggles are unaware that wizards exist, and wizards
(used to magical ways of doing everything) are perplexed and
fascinated by muggle artifacts.
In retrospect it seems completely inevitable that hackers would adopt
this metaphor, and in hacker usage it readily forms compounds such as
muggle-friendly. Compare {luser}, {mundane}, {chainik}, {newbie}.