In TypeScript, an array is a collection of elements, all of which must be of the same type (e.g., numbers, strings, or objects). Arrays are useful for storing lists of data where order matters and where you may need to access or modify elements based on their index. The index in an array starts from 0, meaning the first element is accessed at index 0, the second at index 1, and so on. Arrays in TypeScript are dynamic, meaning their size can grow or shrink as elements are added or removed. You can create arrays using two different syntaxes: `let arr: number[] = [1, 2, 3]` or `let arr: Array = [1, 2, 3]`. TypeScript also supports multi-dimensional arrays and various array methods such as `push`, `pop`, `map`, `filter`, and `reduce`. The TypeScript type system provides safety by enforcing that only elements of the specified type can be added to the array. For example, if you define an array of numbers, trying to add a string will result in a type error. Arrays are frequently used in DSA for implementing algorithms like sorting, searching, and dynamic programming. Mastering arrays and their built-in methods is key to solving many coding challenges efficiently.