Biscuits and Cookies
There is a technical difference. Britain has always had both sorts.
A Biscuit - apart from the US breakfast scone, which is sort of warm stodge - A Biscuit is cut from rolled dough, while a Cookie is made from a dollop of batter. There is a tool called a biscuit cutter.
Industrially things are similar - biscuit dough is rolled and cut (or stamped). Cookies are dropped from a depositor nozzle, sometimes with a wire cutter to interrupt the stream.
Just to complicate the matter, my Mother-in-law came from Canada with a recipe for anzac biscuits, which are deposited and then rolled. Then the Scots have drop scones, which I understand are a weapon of the besieged, used to drop on incoming armies. At least one scottish scone is made of stone.
In the US, as far as I can make out, all styles are called 'cookies', and you have to shop for a cookie cutter. It seems a shame not to have the distinction.
The definitive biscuit is the ginger biscuit, not available in the US as far as I know. Just to confuse you further, the proper name for it in the bakery trade is a 'Ginger Snap'.
Now, let us consider the products of Messers Carr. Until they were bought by United Biscuits they sold four different versions of Carr's water biscuits (High bake, low bake etc). These appear to be now called Water Crackers - perhaps since Kellog acquired the company. This is probably the correct name. Water Crackers originated in the southern states of the USA before their civil war. Carr adapted the principle and made something less sweet and less salty, more like the traditional Bath dry biscuit. But they are undoubtedly crackers - crackers are moulded and cooked simultaneously between heated irons. c.f. Jacob's cream crackers, where the cream is cream of tartar.
Oh, by the way, the proper name for a Bath dry biscuit is a Bath Oliver. Nothing to do with our civil war, they were named for a Dr Oliver who ran a watering place in Bath. The ownership of the recipe has passed hand over hand to a company called Fort, nothing to do with Fortean Times, although they taste the same.