Liz B in the UK emailed to ask me how to interpret English cucumber in an American recipe. And I replied with something like (but I've edited it now):
an English cucumber is just the kind you'd buy normally in a British supermarket as 'a cucumber'. They differ from the ones usually sold in the US, which are shorter, thicker- and smoother-skinned, and have bigger seeds.
So, here's what's called a cucumber in the UK and an English cucumber or seedless cucumber or even burpless cucumber in the US:
Before anyone asks, neither of these are BrE courgettes/AmE zucchini, which were discussed back at the Big List of Vegetables. And if you want to know about pickled cucumbers [if you want to read my RANT about pickled cucumbers], click on those lovely, often misleading words. Oh, and the clipping cuke is an Americanism. We must be very fond of them to give them a nickname.