What is the etymology of "business end"?

What is the origin of the phrase "business end"?

There is no special etymology as such. Business could stand for activity or commercial operation. So business end means the end (could be the tip, as in the business end of the fork) which performs or involves the maximum activity or work.

In a long tournament like the World Cup, the knock-out phase could be called business end, because it is the period of intense activity (and also is commercially most popular) involving the best teams.

It doesn't really have an origin as such. It is just business + end, much the same as pointed end or any other end.

It has been recorded in use since around the first half of the 19th century, at that time usually in reference to actual businesses - "the business end of the street".