A trie, or prefix tree, is a data structure used for efficiently storing and retrieving strings, where each node in the trie represents a character. It’s commonly used in applications like autocomplete, spell checking, and IP routing, where fast lookup of keys or prefixes is important. In TypeScript, you can implement a trie by defining a class `TrieNode`, where each node contains a map (or object) of child nodes and a boolean flag to mark the end of a word. The trie itself can be implemented as a class that contains a root node and methods for inserting, searching, and deleting words. Each word is inserted character by character, following the existing nodes or creating new ones as necessary. To search for a word or prefix, you traverse the trie node by node, following the path corresponding to the characters in the search term. Tries are particularly useful when you need to manage large dictionaries of strings, perform prefix searches, or build efficient data structures for string-matching algorithms. Understanding how to implement and optimize tries can greatly improve performance in text-heavy applications, search engines, or dynamic input suggestions.