"And wtf is a 'stick' of butter?"
Back in the day, the PTB decided that butter for sale should be of a standard weight. This was to keep rogue butter dealers from stealing from the poor ("poor" here meaning "couldn't afford a cow to make their own butter"). They decided butter should come in bricks of one pound (16 American ounces) in weight. To make life easy, each brick was cut (and wrapped) into four equal portions of 4oz each, which also equal 1/2 a cup. These half cup portions soon became known as "sticks" of butter. To further make life a trifle easier, the wrapping for each stick is labeled with markings for 1/3cup, 1/4 cup and individual tablespoons. No need to measure, you cut on the line and use it.