Open Source = the “Atoms” in Our “Digital Periodic Table”
I thought for a while, and came up with the definition in $title, which I think is quite neat.
Just like physical atoms, most open source projects are elementary building blocks which creators can put together to create new things.
Just like atoms, there are some exceptions when just the atoms or just an open source project are end-user products that people want/use directly, without being part of some bigger molecule, such as physical Gold atoms, or a open source end-user product such as Signal. But these are exceptions, most atoms and open source code are building blocks, which are not meaningful in isolation.
This analogy was helpful to me when explaining open source to this non-technical person, as nobody would question the value of e.g. Silicon or Hydrogen, in the same way we don't question the value of Operating Systems or Databases.