Chips. Although very occasionally you will hear crisps.

Often "hot chips" (french fries), as distinct from a "packet of chips" (crisps), but it's contextual: e.g. a Schnitzel with salad and chips, would always be with hot chips.

Crisps. Unless you are referring to a packet of chips, which you may also refer to as a bag of crisps, which you may also call chips. This is on the citizenship test, by the way. Every other answer is “Sir Donald Bradman”.

Crisps has pretty entirely been overtaken by chips. Magnificent word though, sometimes I use it to either be funny or just remember the taste and texture of a sadly underutilised word.

It never applied to hot chips/ fries though, just the other kind.

If you want a raised eyebrow response, just ask "are you going to finish those crisps?"

They'll know what you mean, but they'll still act confused. It's great.

New Zealand uses "chips" for two kinds.

e.g. I'd use the name "chip sandwich" for a sandwich with crisps in them; a "chip butty" is sandwich with thick-cut french fries.

Thinly sliced fried potato in bags = chips.

French fries = hot chips if you need to disambiguate, but usually (eg on a restaurant menu) just chips.

Chips