To personalize something means to change or create it to fit a specific person's preferences, needs, or identity. When you personalize a notebook by writing your name on the cover and decorating it with stickers of your favorite things, you're making it uniquely yours. When a teacher personalizes instruction, she adjusts her lessons to match how each student learns best: some kids might need extra practice problems, while others might benefit from visual diagrams.

The word suggests tailoring something to reflect individual qualities or requirements, going beyond surface-level customization. A birthday card becomes more meaningful when you personalize it with an inside joke or a drawing that connects to your friend's interests. Online services personalize recommendations based on what you've enjoyed before: a music app suggests songs similar to ones you've liked, while a library website might recommend books based on your reading history.

The opposite of personalized is generic or one-size-fits-all. A personalized gift shows you thought about what matters to that specific person, while a generic gift could work for anyone. When doctors personalize treatment plans, they consider each patient's unique situation rather than giving everyone the same advice.