This is the 4744th most frequent Russian word.
заключены
"Заключены" means "enclosed" or "confined," depending on context.
The word "заключены" is used in the past tense passive voice to describe that the action of signing or finalizing the contracts has been completed.
Договоры были заключены вчера.
The contracts were finalized yesterday.
Here, "заключено" derived from "заключены" is used in the sense of incorporating within boundaries.
Это задание должно быть заключено в сроки.
This task must be completed within the deadlines.
"Заключены" in this sentence refers to enclosing or including all participants into a list.