Magick

Why do we spell it with a "k"? Aleister Crowley introduced the use of the "k" to differentiate between stage magic and real magick.
Magick is defined as "a ritual performance or activity believed to influence human or natural events through access to an external mystical force beyond the ordinary human sphere"(1) or "The science and art of causing change to occur in conformity with will using means not currently understood by traditional Western science"(2).
See: White Magick
(1) Encyclopędia Britannica (2) Modern Magick, Donald Michael Kraig, Llewellyn's High Magick Series.