Optimization in WordPress involves improving a website's performance, speed, and user experience to enhance functionality and search engine rankings. Key optimization practices include using caching plugins like WP Super Cache or W3 Total Cache to reduce server load, compressing images for faster load times, and utilizing lightweight themes and plugins. Optimizing the database by cleaning unnecessary data and enabling a Content Delivery Network (CDN) further boosts performance. Regular updates of WordPress core, themes, and plugins ensure security and compatibility. By prioritizing optimization, WordPress sites achieve better speed, higher engagement, and improved SEO, providing a seamless experience for visitors and users alike.