The general public barely understands the difference between a trader and a broker.
For good reasons!
When you watch famous movies such as Wall Street, Boiler Room, the Wolf of Wall Street, the uneducated viewers will tell you that those are movies about greedy traders.
But… they are not!
In Wall Street (1987), Gordon Gecko seems to represent a fund manager, not a trader. In Boiler Room (2000) and the Wolf of Wall street (2013), those movies portray stockbrokers, not traders.
On the other hand, the scene below in Margin Call (2011) shows traders fire selling their books of mortgage bonds. As you will see in the scene below, trading in front of 5 screens is… a boring task to show in a movie.
Therefore, these two minutes are a bit dull where it should be the pinnacle of anxiety for the viewers.
By the way, the “bank traders” have also almost disappeared from the banks. We could still find small desks of exotic OTC. But nothing of what it used to be in size and workforce.
Furthermore, when you check the topic on popular websites such as quora:
You will find detailed explanations about who is doing what in different industries. But they fail to point out the definitive difference between the two of them.
Those answers reason by analogy instead of first principles.
So if we do our best to boil down to the smallest truce.
A broker is risk-neutral
In other words, a broker finds a buyer and a seller and arrange a deal between the two of them without taking risks.
A trader takes on risks
A trader also finds a buyer and a seller, but the risks are transferred from the seller to the trader, AND then from the trader to the buyer.