Page has several meanings:

1. A single sheet of paper in a book, magazine, or notebook. When you read, you turn pages to continue the story. A typical novel might have 300 pages, while a picture book might have only 32. The front and back of each sheet are usually counted as separate pages, so one piece of paper contains two pages. Writers often talk about how many pages they've written that day.
2. To call someone's name publicly to get their attention. Before cell phones existed, airports and hospitals would page people over loudspeakers: “Will passenger Smith please come to gate 12.” Some restaurants still page customers when their table is ready.
3. A young person training to become a knight in medieval times, or a young assistant in a government building. A page in the U.S. Congress helps deliver messages and run errands for senators and representatives. In medieval times, boys around age seven would become pages in noble households, learning manners, riding, and combat before advancing to become squires and eventually knights.