The `<div>` element is a fundamental building block in HTML, used to group and organize content on a webpage. It acts as a container that can hold other HTML elements, such as text, images, and other `<div>`s. By using `<div>`, developers can apply styles and layout properties to multiple elements at once, making it easier to manage the design of a webpage. In web development, `<div>` is often paired with CSS (Cascading Style Sheets) to control the appearance of the content inside. This allows for flexible layouts and responsive designs, which are essential for modern websites. The use of `<div>` helps create a structured and visually appealing user experience.