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. This allows for dynamic repetition based on changing variables. While loops are commonly used in various programming languages, such as Python, Java, and C++. They are particularly useful for tasks where the number of iterations is not known in advance, such as reading data until the end of a file or waiting for user input.