What is core satoshi?

Could you please elaborate on the concept of "core satoshi"? I've encountered this term a few times in my cryptocurrency readings, but I'm still a bit hazy on its exact meaning. I understand that it's somehow related to Bitcoin, but I'm not sure how it fits into the broader cryptocurrency and finance landscape. Is it a technical detail, or does it have practical implications for investors and traders? Would you mind breaking it down for me in a way that's easy to understand? Your insights would be greatly appreciated.