Meaning
What does Alt F4 mean?
Alt + F4 are both keys on the computer keyboard, and when pushed simultaneously, they cause the active window to close, in most windows systems.
It is used to trick people online in different situations, for example; Someone asks in an online forum how to copy a text.
The prankster will then comment that he must mark the desired text then press Alt + F4, causing the victims window to close, forcing them to have to find the page they were using again.
It is used as a prank towards people not familiar with the combination – or with computer systems in general, and will obviously cause annoyance when the used window unexpectedly shuts.
Origin
What's the origin of Alt F4?
MIRC was a popular multiple internet relay program in the 90’s – 00’s, and the prank was likely to first take place on this platform, as it was used mostly by young people, both beginners, and more experienced users.
MIRC also did not have a confirmation pop-up before closing down the active window, making the prank successful.
Spread & Usage
How did Alt F4 spread?
As it is a computer feature, the term is used mostly online.
Pranksters will comment Alt + F4 under posts asking for assistance, but it is also seen in the meme world. People will create a meme which falsely advises people to click Alt + F4, indicating that something cool will happen.

External resources
- Know Your Meme – Alt F4