Loess is a fine, dust-like material comprised of silt that settles on hilltops. It is formed through the accumulation of wind-blown sediments, typically from areas such as river valleys or deserts. To find this information, you can search for "What is loess?" on a search engine, such as Google. This will provide you with various sources, such as websites or articles, that explain the definition and formation of loess. Reading these sources will help you further understand the topic.