Wikipedia, our old friend, lists at least six types of mandrels:
- Mandrel (bending), a device inserted into a pipe or tube to keep it from collapsing during bending
- Mandrel (catheter), the metal guide for flexible catheters
- Mandrel (codename), a Royal Air Force device for the jamming of German radars during World War II
- Mandrel Screen, a patrol line of Royal Air Force aircraft employing the Mandrel jammer during World War II
- Mandrel wrapping, a technique used in multimode fiberoptics
- Operation Mandrel, a series of 53 American nuclear tests in 1969 and 1970
The first of these was the one I came across initially. It's used in beadwork, apparently, although my wife, when she did beadwork, never had one of them. The second usage makes me feel a little queasy, since I had a good deal to do with catheters a couple of years ago and don't really like to think about them much. However, Wikipedia notes that this device is more often called a mandrin (not to be confused with the 1962 movie of the same name - or even the 1924 film or the 1947 one, or the TV series - Mandrin is the name of the main character.)
Three of the other meanings have military connections; why would the military pick up on a word like this as a codename, you wonder? What's the connection between a beadwork device and a jamming device?
As for the sixth usage, mandrel wrapping, this is described in its introduction on Wikipedia in the following way: mandrel wrapping is a technique used to preferentially attenuate high-order mode power of a propagating optical signal. Consequently, if the fibre is propagating substantial energy in affected modes, the modal distribution will be changed.
I love words, as I said, but I love them to make sense. I haven't any idea what 'preferentially attenuate high-order mode power of a propagating optical signal' means. But then I guess the person who wrote that may not know what rallentando, lento, accidentals, naturals, arpeggios mean, though they're commonplace in my world!