1) Short-hand version of "Windows XP," one of Microsoft's operating systems for PCs.
2) The first two letters of the Greek word
XRISTOS, Christ; -- an abbreviation used with the letters separate or,
oftener, in a
monogram, often inclosed in a circle, as a symbol or emblem of Christ. It use as an emblem was introduced by Constantine the Great, whence it is known as the Constantinian symbol, or monogram.
1) "XP is so much more stable than
98, but the work space is so small and they re-arranged the
UI... again!"
2) "WHOA! I didn't know XP is the shortened Greek version of
Christ!"