A loop is a programming structure that repeats a block of code multiple times until a specified condition is met. Loops are commonly used to automate repetitive tasks, making code more efficient and easier to manage. There are different types of loops, such as the for loop, which repeats a set number of times, and the while loop, which continues until a certain condition becomes false. In addition to simplifying code, loops can help in processing data collections, like arrays or lists. For example, a loop can be used to iterate through each item in a list and perform actions on each element, such as calculating a total or modifying values.