To become means to change into something different or to grow into a new state. When a caterpillar becomes a butterfly, it transforms completely. When water becomes ice, it changes form but remains the same substance. When you practice piano every day and eventually become skilled at it, you've developed an ability you didn't have before.

The word captures the process of transformation over time. A shy kindergartener might become confident by fifth grade. A seed becomes a plant. A student who struggles with fractions might become comfortable with them through practice and patience.

Become often appears in questions about the future: “What do you want to become when you grow up?” This really asks what kind of person you want to develop into, not just what job you'll have. Someone might become a teacher, but they might also become kind, become brave, or become wise.

You can also use become to describe what suits or fits someone well, as in “That blue jacket really becomes you,” though this usage sounds old-fashioned today. The more common meaning focuses on change and transformation: the journey from what something is now to what it will be later.