Glossary of Terms:
 
sequencer
A software program or hardware device that can record and playback MIDI data in order to control the performance of MIDI controlled musical instruments or devices in a series of timed steps. Also referred to as a MIDI sequencer.
Source: Recording Institute of Detroit

Also refered as:
  MIDI sequencer
Related terms:
  MIDI   MIDI Machine Control   MIDI controller   MIDI program change