A Simm is any mountain in Britain or Ireland with a prominence over 30m and a height above 600m.
A Hewitt (Hill in England, Wales and Ireland over Two Thousand) is a mountain in England, Wales or Ireland with a height over 2,000ft and a prominence greater then 30m.
A Nuttall is a mountain in England or Wales with a height over 2000ft and a prominence greater then 15m
A Bridge is a peak featured in George Bridge's book: Mountains of England and Wales: Tables of the 2000ft Summits
A Buxton & Lewis is a peak featured in the book by Chris Buxton and Gwyn Lewis, "Mountain Summits of England and Wales".