I was wondering whether you guys define both '.....' and '-----' as dotted lines. The latter is often shown in lower case, but I'm thinking of it more in terms of layout programs rather than typography anyway. I've have also seen 'dashed' for the second, though I'm not sure if that's a US usage or not. It makes sense to me but sounds a little weird. I think 'broken line' it pretty common too. Any comments?

Dashed works for me. We see both in charts and diagrams of all sorts.

I like "dashed", too. After all, that's what it is. Makes a difference in origami, too, between mountain and valley folds.

dotted and dashed are two separate border styles in css coding.

> dotted and dashed are two separate border styles in css coding.

Right. Thing is in the Springer Computing Dictionary it gives 'dotted' for, well, 'dashed' lines. This is why I guessed that 'dashed' maybe USn and UK English uses 'dotted' for both. Dictionary.com gives 'dashed' as a synonym of dotted:
http://dictionary.reference.com/search?q=dashed

ah.

I'm wondering if perhaps the specificity (in usage, anyway) of the terms hasn't changed lately because of the whole "dot" thing.

Living in the UK, I don't think I ever heard "dashed line". Forms would require you to "Sign on the dotted line" and while most often these were indeed composed of dots, I have occasionally seen the one that was made out of dashes and still in the "dotted line" category, though...