Определение и Значение "(at the) top of the agenda"

What is the origin of the idiom "top of the agenda" and when to use it?

The exact origin of the idiom "top of the agenda" is uncertain, but it is believed to have originated in the United States in the early 20th century. There are a few different theories about its origins, but the most likely is that it refers to the importance of tasks or items that are considered to be most urgent or important. This phrase is used to mean that something is the most important or urgent thing to do or consider. It is often used in the context of business or politics, but it can also be used in more informal settings.