In the past I worked with cranes a lot, on repairs and testing, one of the actions on the old rope controlled jibs (no hydraulics) was Derrick In and Derrick Out, this was dropping or raising the jib. My understanding of it, and the fact some are on a turntable is non-consequential. The CMP Derrick lorry does just that, it raises and lowers the jib/derrick.
Also ...just to throw another spanner in the works, the old oil wells with the pylon like structure, was called a derrick and all it did was to hoist up and down within the structure.
