An algorithm in computer science functions as a step-by-step procedure or formula for solving a problem or performing a task. Algorithms are fundamental in programming, providing a logical sequence to ensure that computers process data efficiently and correctly. They can range from simple operations, like sorting numbers, to complex processes utilized in machine learning and artificial intelligence. A well-designed algorithm increases efficiency and optimizes resource usage, influencing overall system performance and user experience. Thus, algorithms are essential for both practical applications and theoretical understanding in computer science.