Exaptation is one of my absolute favorite observations in nature and conceptually one of my favorite ideas of all time. Technology is full of these ideas and is a key type of innovation in tech. The idea originally comes from Stephen Jay Gould, who observed how biological functions would often be cloned, mutate over time and acquire new functionality.
A definition from chatgpt:
Exaptation is the process by which a feature, idea, or technology originally developed for one purpose is adapted or co-opted for a different, often unrelated purpose.
And a few random examples pulled from the web: