A "while loop" is a programming construct that repeatedly executes a block of code as long as a specified condition remains true. It starts by evaluating the condition; if it is true, the code inside the loop runs. After executing the code, the condition is checked again, and this process continues until the condition becomes false. While loops are useful for tasks that require repetition, such as processing items in a list or waiting for user input. They help automate repetitive tasks without needing to write the same code multiple times, making programs more efficient and easier to manage.