I once attended a very serious lecture on defenestration, the ancient and highly specific art of throwing someone-or something-out of a window.
The professor began: "The word comes from the Latin de, meaning 'out of,' and fenestra, meaning 'window.'"
At that point, one student raised his hand and asked, "So what's the technical term for throwing someone through a door?"
The professor sighed. "That would be dedoorstration."
"Is that a real word?"
"No."
"Could it become one?"
"Not if you keep interrupting."
The student stood up, marched toward the window, and declared, "Then I shall make history!"
The professor shouted, "Wait! You can't just invent terminology by throwing yourself out of a window!"
The student paused halfway through climbing onto the sill.
"Why not?"
"Because that would be self-defenestration."
The student considered this carefully.
"So... a window of opportunity?"
And that, according to the professor, was the moment the lecture went completely out the window.