Definition: "JSTree" is a tool for creating dynamic, scalable tree structures using HTML5 markup. Detailed definition: JSTree is designed to be as flexible and adaptable as possible, allowing developers to easily create and manipulate complex hierarchical structures in their websites or apps without needing extensive knowledge of XML, CSS, JavaScript, or database querying. It's particularly useful when integrating into existing applications that rely on these types of visual representations for navigation or layout management.