@ Dave in the States
Router vs router: in the UK, it's pronounced the same as 'route' - but to further clarify, it's like "root" in "root beer" (which incidentally is called "ginger beer").
What I'd like to have properly classified are food items. As far as I'm aware, all of the following similar items have different meanings for Yanks and Brits:
In the UK, it's what a Yank would call a "cookie" - a hard sweet baked thing. In the US, it's a softer thing similar to a UK "scone".
In the UK, it's usually specifically a chocolate-chip cookie (although in Scotland, a plain 'cookie'). For the US, it's the same range of what Brits would call biscuits.
In the UK, it's a soft, baked bread-type thing, often served with cream or jam. In the US, this is what Yanks refer to as a "biscuit", while a scone for Yanks is made differently and more often crumbly than flaky, and in some regions refers to a deep-fried flattened bread (similar to a bannock).
So, in summary, a translation for Brits going to the USA:
Biscuit = a quick bread similar to a scone
Cookie = a biscuit
Scone = variation of a scone made with shortening, or a deep-fried flat bread
And a translation for Yanks visiting the UK:
Biscuit = a cookie
Cookie = a cookie
Scone = a biscuit
There were a couple of others along the same lines, but I forget them. It's really hard to make parallels with these foods in UK and US, because the same words exist but mean different things, and to not use the correct word means a long-winded explanation instead. I hope this made sense because it was damnedably hard to write.