The act of passing through a window on your way down to a fatal impact with Mother Earth.
The manner of passing through this portal of doom can vary of course. Those with an overly refined sense of the dramatic may choose to jump through of their own accord. Others need more encouragement, often by being forcibly hurled.
Having characters thrown or blasted through a window is surprisingly popular in cinema. Directors probably think it looks exciting to see people plummet from the safety of a room down to their deaths - and if slo-mo shards of glass can be seen glittering around the screen so much the better.
Once you've seen it dozens of times in every action movie going though, it just becomes yet another cliche we like to discourage here on the MDDB.
By the way, we're not overly fussy on how we define a window here - a glass patio door would probably apply for example, provided there was some kind of drop on the other side.