ARIA landmarks are special roles assigned to sections of a webpage to improve navigation for users of assistive technologies. These landmarks help users quickly jump to different parts of the page, such as the main content, navigation, or search areas.

Semantic HTML refers to the use of HTML tags that convey the meaning of the content they enclose. While ARIA can add accessibility information, using semantic HTML is the first step in creating accessible web content. ARIA should complement, not replace, semantic HTML.

Live regions are parts of a webpage that dynamically update and need to be communicated to users immediately. ARIA attributes can designate these regions so that screen readers notify users of changes in real-time without losing focus on their current task.

Focus management involves controlling the user's navigation focus within web applications. ARIA attributes help manage focus, ensuring that users can navigate efficiently through interactive components using a keyboard or other assistive devices.

Screen reader compatibility is crucial for web accessibility. ARIA attributes enhance how screen readers interpret and relay web content to users, making it easier for visually impaired individuals to understand and interact with web pages.