One’s man tuh-MAH-toe is another man’s tuh-MAY-toh, much like one man’s fridge is another’s refrigerator. The same goes for trousers and pants, braces and suspenders and flip-flops and, er, thongs.
So it is with dress shoes. By its American definition, a dress shoe is anything that’s not a sneaker, boot or any style of footwear that exposes your feet – which means a brogue, a Derby, an Oxford or a monk-strap shoe. But the average Briton will tell you these are ‘smart shoes’, and in the UK, a ‘dress shoe’ means something you’d wear to a black-tie ball or similarly formal event – like a patent plain-toe Oxford, for example.
To save this turning into any more of a lecture on the semantics of shoe-related terms than it needs to be, Jamie, I’m going to lazily assume you mean the latter.
In which case, a dress shoe is strictly speaking a highly polished – or patent – black plain-toe or cap-toe Oxford. And yes, you need one. (Two, actually, if at all possible.) More broadly speaking, highly polished black leather Derby shoes, black velvet Derby shoes and slippers (provided they’re the formal, heeled kind and not the sort you stumble around a hotel room in) are all dress shoes, too.
So take your pick, and if you don’t know already, do yourself a favour by learning how to care for them here.