To "apply" means to put something into action or use it in a practical way. For example, when you learn a new skill, such as cooking, you can apply that knowledge by preparing meals at home. This process helps reinforce what you've learned and makes it more useful in everyday life. In various fields, such as science or business, applying theories or concepts can lead to real-world solutions. For instance, a scientist might apply a new method to conduct experiments, while a manager might apply strategic planning to improve team performance. This practical use of knowledge is essential for progress and innovation.