An overview of a situation is a general understanding or description of it as a whole.
双语例句
例： The central section of the book is a historical overview of drug use.
本书的中心部分对毒品的使用做了历史概述。
例： The purpose of this book is to provide an overview of the mammals of the world.
该书旨在提供一份关于世界哺乳动物的概述。 。