Define the term "iteration" in programming languages.

In programming languages, iteration refers to the process of repeatedly executing a block of code until a certain condition is met.

Iteration is a fundamental concept in computer programming. It is a control flow mechanism that allows a set of instructions, also known as a block of code, to be executed repeatedly. This repetition can occur a specific number of times, or until a certain condition is met. The condition is usually a logical expression that evaluates to either true or false. If the condition is true, the loop continues to iterate. If it's false, the loop ends and the program moves on to the next block of code.

There are several types of iteration structures in programming, including 'for' loops, 'while' loops, and 'do-while' loops. A 'for' loop is typically used when the number of iterations is known in advance. It has a counter that increments or decrements with each iteration, and the loop continues until the counter reaches a specified value. A 'while' loop, on the other hand, continues to iterate as long as a certain condition remains true. The condition is checked before each iteration, and if it's false, the loop is skipped entirely. A 'do-while' loop is similar to a 'while' loop, but the condition is checked after each iteration, ensuring that the loop is executed at least once.

Iteration is a powerful tool in programming because it allows programmers to automate repetitive tasks, making their code more efficient and easier to read. For example, if you wanted to print the numbers 1 to 10, you could write ten separate print statements, or you could use a 'for' loop to iterate over the range of numbers, printing each one in turn. The latter approach is not only more concise, but also more flexible, as it can easily be adapted to print any range of numbers.

In conclusion, understanding iteration is crucial for anyone learning to program. It's a fundamental concept that underpins many of the tasks that computers are used for, from processing large datasets to controlling the flow of user interactions in a software application.