Stand to sort out letters (7)
I believe the answer is:
trestle
'stand' is the definition.
(stand which supports something else)
'sort out letters' is the wordplay.
'sort out' indicates anagramming the letters.
'letters' is an anagram of 'TRESTLE'.
'to' acts as a link.
(Other definitions for trestle that I've seen before include "Framework to support a flat surface -- letters (anag)" , "Simple table support" , "Letters (anag) - table" , "support of growth" , "Support for table top" .)