The Matterhorn, for one (3)
I believe the answer is:
alp
'the matterhorn for one' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for alp that I've seen before include "high point" , "High mountain" , "Mont Blanc, for example" , "Swiss mountain" , "One of a European mountain range" .)