The term "key concepts" refers to fundamental ideas or principles that serve as a foundation for understanding and explaining complex topics. These are essential elements that provide clarity, coherence, and organization to a subject matter, making it easier to grasp and retain information. In other words, key concepts represent the core knowledge that is necessary to comprehend a particular field of study or area of interest. They act as building blocks for constructing an understanding of a topic by breaking down complex ideas into simpler components.