The regions, with their names and numbering are taken from Munro's Tables.
The Munros
A Munro is a Scottish mountain over 3000 ft in height, distinct and separate from its surrounding mountains. Munro's Tables were originally compiled in 1891 by Sir Hugh Munro, but are now revised and maintained by the Scottish Mountaineering Club.
(Munros appear as Class=M on this website).
A Munro Top is also a summit over 3000 ft, but considered to be a subsidiary top of a Munro.
(Munro Tops appear as Class=MT on this website).
The Murdos
A Murdo is a Scottish mountain over 3000ft (914.4m) in height, with a drop of at least 30 metres (98 feet) on all sides. All Murdos except Beinn a'Chroin (W top) are also Munros or Munro Tops. All Munros are Murdos, but not all Munro Tops are Murdos.
A subMurdo is a hill which just fails (by up to 10m) to qualify on the drop rule, i.e. over 3000ft with 20-29m drop.
(Murdos appear as Class=Mur on this website, and subMurdos as Class=sMur).