In computing, an algorithm is a step-by-step set of instructions or rules designed to perform a specific task or solve a particular problem. It defines a clear sequence of actions or decisions to be followed to achieve a desired outcome. Algorithms are fundamental to computer science and are used in various applications, such as sorting data, searching for information, and performing calculations. They can be implemented in different programming languages and can vary in complexity, efficiency, and approach depending on the problem they address.