A Prefix Tree, also known as a Trie, is a specialized data structure used to store a dynamic set of strings. Each node in the tree represents a single character of a string, and paths from the root to the leaves represent the strings stored in the tree. This structure allows for efficient retrieval, insertion, and deletion of strings, making it particularly useful for applications like autocomplete and spell checking. In a Prefix Tree, common prefixes are shared among strings, which helps save space. For example, the words "cat," "car," and "cart" would share the initial nodes for 'c', 'a', and 'r'. This organization enables quick searches, as you can traverse the tree based on the characters of the string you are looking for.