This is the 41st most frequent Finnish word.
mitä
"What."
'Mitä' is used as an interrogative pronoun meaning 'what' to ask about an action or activity.
Mitä teet huomenna?
What are you doing tomorrow?
'Mitä' is used as a relative pronoun citing the object of the subordinate clause.
En tiedä, mitä tapahtui eilen.
I don't know what happened yesterday.
'Mitä' is used in a similar role to a relative pronoun in English, connecting the main clause to the subordinate clause while specifying the object.