What does "monolithic" mean?

I've seen it in the context of classes. I suspect it means that the class could use being broken down into logical subunits, but I can't find a good definition. Could you give some examples?

Thanks for the help.

Edit: I love the smart replies, but I'm obviously referring to "monolithic" within a software context. I know about monoliths, megaliths, dolmens, and all the stone-related contexts. Gee, I have enough of them in my country...