This is the 260th most frequent Estonian word.
millele
"To which" or "on which."
Estonian 'millele' functions as a relative pronoun referring to an antecedent (question).
See on küsimus, millele ma vastan homme.
This is a question to which I will answer tomorrow.
Estonian 'millele' is used in the context of a problem (with an implied action or condition) being discussed.
Millal leiame lahenduse probleemile, millele ei näi olevat vastust?
When will we find a solution to the problem for which there seems to be no answer?
Estonian 'millele' denotes the object (chair) upon which the action occurs.