The <main> element defines the most important and unique content of the page. It can't contain repetitive elements like navigation links, menus, site logos, and search forms that users can meet throughout the website.

From the accessibility standpoint, the <main> element acts as a prominent landmark. Simply put, this tag indicates the largest and most crucial part of the page to screenreader users so they can skip the navigation part and jump right into the content.

The HTML page can contain only one <main> element, and it can't be a child of an <article>, <aside>, <footer>, <header>, or <nav> element.