The Prime Minister's executive office is usually called the Office of the Prime Minister in the case of the Canada and other Commonwealth countries, it is called Cabinet Office in United Kingdom. Some Prime Minister's office do include the role of Cabinet. In other countries, it is called the Prime Minister's Department or the Department of the Prime Minister and Cabinet as for Australia.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is the Cabinet in Canada?
unanswerable