Why are the winds that blow from the subtropical high pressure systems (sthp) called the trade winds?

The reason why the winds that blow from the subtropical high pressure system is called the trade wind is because in the era of sailing ships,regions of constant winds were much were appreciated. They made trade around the world possible. That's the reason why it's called the trade winds:)

Hope this helps:)

D.haka is the first answer and a.canberra is the second answer