Master keyboard

From AudioLexic

A master keyboard is a keyboard with no onboard sounds. It is used to pilot other keyboards, expanders or virtual instruments. Beside the keyboard itself it can have some controllers like sliders, potentiometers, encoders to modify parameters like volume, envelope, sustain… without moving away from the keyboard. It can also have buttons with basic functions like start/stop to control a Digital Audio Workstation

Master keyboards issue MIDI and SYSEX messages.

Usually, master keyboard have a split function where you can divide the keyboard between different MIDI channels. They can have a memory to recall later the settings.