Bree-hill

This is not so strange as it sounds. Duplication of elements like this often occurs in real place names, with perhaps the most extreme example being Torpenhow Hill in Cumbria, England, whose name means 'Hill Hill Hill Hill'. More directly relevant to our topic here is Brill on the border of Oxfordshire and Buckinghamshire, whose name comes from Bre hyll. That's literally 'Bree-hill', and Tolkien acknowledges a connection with his own 'Bree-hill' in Middle-earth.