Slang for
Power Distribution Device, or PD. May provide 120 or 208V power and over-
current protection for moving lights, audio racks, AV equipment, chain hoists,
etc., and output via
Socapex,
L6-20, L21-30,
NEMA 5-15 (
Edison) outlets.

Photo courtesy
Motion Labs.
In the US, portable power distribution equipment should be built and
listed to the
UL1640 standard. See also
http://www.controlbooth.com/forums/l...ge-meters.html.