Letter from Poles in translation (7)
I believe the answer is:
epsilon
'letter' is the definition.
(epsilon is a kind of letter)
'poles in translation' is the wordplay.
'translation' is an anagram indicator.
'poles'+'in'='polesin'
'polesin' anagrammed gives 'EPSILON'.
'from' is the link.
(Other definitions for epsilon that I've seen before include "character in Greece" , "Fifth brightest star in a constellation" , "Foreign character" , "5th letter of the Greek alphabet" , "Greek letter - pinoles (anag)" .)