The Collaborative International Dictionary of English v.0.48:

Copple \Cop"ple\, n. [A dim. of Cop.]
   Something rising in a conical shape; specifically, a hill
   rising to a point.
   [1913 Webster]

         A low cape, and upon it a copple not very high.
                                                  --Hakluyt.
   [1913 Webster]