Google APIs (or Google AJAX APIs) is a set of JavaScript APIs developed by Google that allows interaction with Google Services and integration of rich, multimedia, search or feed-based Internet content into web applications. They extensively use AJAX scripting and can be easily loaded using Google Loader.
Google AJAX APIs is a JavaScript library to integrate rich, multimedia, search, or feed-based Internet content into web applications/pages, organized by Google. They can be used by third parties to place rich Ajax content on web pages.