We have an ex-pat friend living in Texas who asked if we could send him some crisps to remind him of home. But what to put on the customs declaration!
According to the Oxford Dictionaries Blogg, slices of bread or fruit, were known as "chips" in medieval England, but the usage died out. The Americans began making lightly-fried, thinly cut potatoes slices in 1824 in Saratoga Springs, NY, and these became known as Saratoga Chips. Later restaurants invented a deep fried version known as German Fries. At the outbreak of World War I they were renamed French Fries for patriotic reasons.
The British fell in love with deep fried fish and potatoes from 1860, and called them potato chips, like their American cousins. When thinly cut fried potato-slices made their way across the Atlantic in the 1920s they were called potato crisps in the UK to distinguish them from chips.
So "chips" in the UK are "fries" in the US, and "crisps" are "chips" in the US.
Just to confuse things, in the late 20th century deep fried fish and potatoes made their way to North America, and these are now known as "fish and chips"!