HTML5 (Hypertext Markup Language 5) is the latest version of the HTML standard, used for structuring and presenting content on the web. It introduces new features and improvements over its predecessors, HTML4 and XHTML. Here are some key points about HTML5:

1. Semantic Elements: HTML5 introduces a set of semantic elements that provide more meaningful structure and improve accessibility. These elements include <header>, <nav>, <article>, <section>, <aside>, <footer>, and more. Semantic elements help search engines and assistive technologies better understand the content and its context.
2. Multimedia Support: HTML5 includes native support for multimedia content, eliminating the need for third-party plugins like Adobe Flash. It introduces new elements like <video> and <audio> for embedding video and audio content directly into web pages. Developers can specify multiple source formats and control playback using JavaScript.
3. Improved Forms: HTML5 brings enhancements to form handling and validation. It introduces new input types such as date, email, URL, number, and more, making it easier to capture specific types of data and provide better user experiences. HTML5 also introduces attributes like required, pattern, and placeholder for form validation and user guidance.
4. Canvas and Graphics: HTML5 introduces the <canvas> element, which allows dynamic rendering of graphics, animations, and interactive visualizations using JavaScript. The canvas element provides a drawing API that developers can use to create games, charts, image manipulation, and other graphical effects.
5. Geolocation: HTML5 includes a Geolocation API that allows web applications to access the user’s geographical location, with their permission. This enables the development of location-aware applications and services, such as mapping, local search, and location-based recommendations.
6. Offline Web Applications: HTML5 provides features for creating offline web applications. The Application Cache (AppCache) allows developers to specify which files should be cached and available for offline use. Local Storage and Session Storage provide client-side storage options to store data on the user’s device.
7. Drag and Drop: HTML5 introduces the ability to drag and drop elements within a web page. Developers can implement drag-and-drop functionality for elements like images, files, or other elements, allowing users to interact with the content more intuitively.
8. Responsive Design: HTML5, along with CSS3, facilitates responsive web design. It provides media queries, which allow developers to apply different styles based on the screen size and device capabilities. This helps create websites that adapt and provide an optimal user experience on various devices, including desktops, tablets, and smartphones.
9. Accessibility: HTML5 puts a greater emphasis on accessibility by introducing new elements and attributes that improve the accessibility of web content. Semantically structured markup, ARIA (Accessible Rich Internet Applications) roles and attributes, and other features help developers create more inclusive and accessible websites.

HTML5 is widely supported by modern web browsers, making it a versatile and powerful tool for web development. It provides developers with a range of new features and capabilities to create interactive, multimedia-rich, and accessible websites and web applications.