Can some one help me? I've been looking at a lot of American recipes and I'm having a bad time with the use of the term 'cup'.

I understand it when it refers to a liquid, but I keep finding it being used for things like flour, vegetables etc. I 've looked at loads of sites for equivalent weights & measures, but none of refer to "cups' as a dry weight. Is there an approximate weight for a 'cup' or is it really that variable?

Sort me out, you lot know everything!

TTFN M'Lady P.