What physically is a bit?

Excuse me, but could you please clarify something for me? I've been hearing a lot about bits in the context of cryptocurrency and digital data, but I'm still a bit confused about what a bit actually is, physically speaking. Is it a tangible thing, like a coin or a piece of paper? Or is it more of an abstract concept? I'm hoping you can provide a simple, yet comprehensive explanation that can help me understand the physical nature of a bit.