A letter from Ruby (in Polish?) (3)
I believe the answer is:
rub
'polish?' is the definition.
(polish meaning rub to make shiny)
'a letter from ruby' is the wordplay.
'a letter' becomes 'y' (Y is a letter of the alphabet).
'from' suggests deleting specific letters.
'ruby' with 'y' taken away is 'RUB'.
'in' is the link.
(Other definitions for rub that I've seen before include "Massage or buff" , "Copy (a church brass)" , "Ointment; copy (a brass)" , "Apply friction to - difficulty" , "Polish by friction" .)