Har di Har

"X" is a common name given to all such corresponding artworks of same kind associated with a concept.

The "X" is largely exploited in various high power, and high voltage regions and generally to signify ill will or doom.

Originally it has its roots to a British captain who is credited for "X" near 18th century.

The term itself date further back in time to popular works of a lesser known author (whose name i shall not reveal, because google knows him well) who incorporated this name into his most popular book about the concept in question.

In the US Army four squadrons of the Fifth air force under George C Kenny is named "X"

What is "X"?