This is the 130th most frequent Finnish word.
tehty
"Tehty" means "done" or "made" in English.
The word 'tehty' (past participle of 'tehdä') here describes the completed state of the action (the work being done).
Tämä työ on tehty huolellisesti.
This work has been done carefully.
In this sentence, 'tehty' is used as part of a passive construction to express that the arrangements were completed.
Kaikki järjestelyt oli tehty etukäteen.
All arrangements had been made in advance.
Here 'tehty' is used to denote that the cookies were created through an action (baking, indicated with 'tehty').