1. （船舶上用的）吊杆式起货设备
A derrick is a machine that is used to move cargo on a ship by lifting it in the air.

2. (油井上方的)井架，钻塔
A derrick is a tower built over an oil well which is used to raise and lower the drill.

1. a simple crane having lifting tackle slung from a boom

2. a framework erected over an oil well to allow drill tubes to be raised and lowered