Indexed addressing is a method used in computer architecture to access data in memory. In this approach, an index register holds a value that points to a specific location in memory. This allows for efficient retrieval of data, especially in arrays or lists, by adding the index value to a base address. When a program needs to access an element, it calculates the effective address by combining the base address with the index. This technique simplifies the process of accessing sequential data and enhances performance, making it a common choice in programming languages and systems that require fast data manipulation, such as C or assembly language.