The translucent filter material place in front of lanterns to create a coloured illumination. Colour filters can be made of glass or gelatine, hence Gel, but today are usually made from a synthetic plastic material.
Gels in a Gel Frame or Gel Holder.
A type of colour changer on a follow spot.
Overloading a piece of audio equipment by feeding in a signal too great for the unit to handle, thereby leading to distortion.
‘G’ or ‘C’ clamps are normally attached to lanterns and are used to fasten them to the lighting bars or battens.
G Clamp 
C Clamp
A repeated sequence of changing lighting states.
A sound or light control circuit.
A motorised winch that uses metal chain to lift heavy objects. Widespread usage in the concert production industry to fly speakers and lighting equipment above a stage.
The middle of the acting area. Abbrev. CS.