Moor

From the Old English mōr of Germanic origin. In Scotland "muir".

A complex mosaic of heather, bilberry, grass and moss communities on acid soils.  Typically understood to be an upland landscape largely tree less but moor has been used to describe any tract of open countryside e.g. Sedgemoor. 

Frank Watson Elgee distinguished between Fat Moor, (thick peat) Thin Moor (thin peat) and Mosses (deep peat).

UK Biodiversity Framework

More detailed definitions are provided by the UK Biodiversity Framework.  Here moors fall in to National Vegetation Classification Mires (M1-M38) and Heaths (H1-H22). 

During Phase 1 Habitat Classification moor was covered by D: Heathland and E: Mire.