AJAX, which stands for Asynchronous JavaScript and XML, is a web development technique that allows web pages to update content without needing to reload the entire page. This means that when you interact with a website, like submitting a form or clicking a button, only a small part of the page can change, making the experience faster and smoother. By using AJAX, developers can create more dynamic and responsive applications, enhancing user experience. For example, when you search for something on Google, AJAX helps display results instantly without refreshing the whole page, allowing for seamless interaction and quicker access to information.