What is a bit role in acting?

I'm curious, could you please explain to me what exactly a bit role is in the context of acting? I've heard the term used before, but I'm not entirely sure what it entails. Are these roles typically smaller or less significant compared to leading roles? And if so, how do actors who take on bit roles typically view their contributions to a production? It would be great if you could provide some insight into this aspect of the acting industry.