A device for controlling the lights using a series of faders and buttons. Some (digital) desks are automated but most are controlled by an operator.
The lighting desk comes in two main types, analogue and digital
Send signals to the Dimmers using a series of cores in a cable, these cores carry a signal (there are a number of different formats but the most common is 0V = 0%, 10V = 100%). Analogue desks are rarely made for anything but the smallest applications anymore.
Send signals to the Dimmers and moving lights via the DMX protocol. The digital desk is much more powerful than the analogue desk. Digital desks come in a variety of sizes from 6 channel upwards (>100 channels). Common features include cue stacks and submasters.