- Machinery. a jib crane having a boom hinged near the base of the mast so as to rotate about the mast, for moving a load toward or away from the mast by raising or lowering the boom.
- Also called oil derrick. the towerlike framework over an oil well or the like.
- a boom for lifting cargo, pivoted at its inner end to a ship's mast or kingpost, and raised and supported at its outer end by topping lifts. (http://dictionary.reference.com/browse/derrick)
"Because they were the size of derricks, its arms moved slowly, traversing enormous distances, but they never stopped moving."
- Lev Grossman, The Magician King