Prerequisite is something you must complete or have before you can move on to the next thing. Think of prerequisites as the building blocks you need before you can reach the next level.

In school, prerequisites are common. You typically need to finish basic algebra before taking geometry because you'll use algebra skills to solve geometry problems. Learning to multiply is a prerequisite for learning long division. Many middle schools require a certain reading level as a prerequisite for advanced English classes.

Prerequisites exist outside school too. Before you can get a driver's license, completing driver's education is usually a prerequisite. If you want to join an advanced chess club, knowing how the pieces move might be a prerequisite. A summer camp might list “must be able to swim 25 yards” as a prerequisite for the kayaking program.

Prerequisites serve a real purpose: they exist because the next step genuinely requires skills or knowledge from the earlier one. Without the prerequisite, you'd struggle or feel lost. Meeting prerequisites means you're ready and prepared to succeed. When you've completed all the prerequisites for something challenging, you can approach it with confidence.

As an adjective, prerequisite describes something required beforehand, like a prerequisite course or a prerequisite skill.