Pared stem at the centre of the mountain ridge (5)
I believe the answer is:
arete
'mountain ridge' is the definition.
(I've seen this before)
'pared stem at the centre of the' is the wordplay.
'pared stem' becomes 'are' (I am not sure about this - if you are sure you should believe this answer much more).
'at' says to put letters next to each other.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'centre of' means to look at the middle letters.
'the' becomes 'definite article'.
The central letter of 'definitearticle' is 'e'.
'are'+'t'+'e'='ARETE'
Can you help me to learn more?
(Other definitions for arete that I've seen before include "Narrow mountain ridge - eater (anag)" , "Sharp ridge on mountain, with a tree" , "part of mountain range" , "Glacial ridge" , "feature of range" .)