In Britain, the Ordnance Survey uses whatever the local name is to describe high lands. Throughout England, Wales and Ireland, it is agreed that those above 2,000 feet qualify as �mountains'. Some people maintain, however, that a mountain must have a specific �peak'; on that basis, Kinder Scout - the highest area of Derbyshire's Peak District at 2,087 feet - is just moorland rather than mountain, despite the area's name!
In Scotland, there are various names for different mountain-heights...2,000 - 2,499 feet are Grahams, 2,500 - 2,999 feet are Corbetts and 3000 feet plus are Munros. The last of these is now also applied to mountains in England, Wales and Ireland.
So, yes...there are some guidelines!