In
England what we call cookies are called biscuits. To put a finer point on it, as explained to me by one of the
Brit noders, many biscuits are cookies but you might not call creamier cookies biscuits.
Crackers and the like would also count as biscuits, but they're not the sort of thing the English would normally think of when you talk about biscuits.
In America it's more straightforward, especially in the South. A biscuit is a fluffy bread, usually eaten with lots of butter and perhaps some jam or jelly.
So popular is the biscuit in the South, there are sayings such as, "Well, butter my butt and call me a biscuit!" (This would indicate surprise at some occurrence.)