Page

A page can be different things:

 Usually, a page is a physical sheet of paper in a book, magazine, newspaper etc. When a page is not in a book (etc.) it is a sheet or piece of paper.
 When we talk about computers, a page is also a common abbreviation in net jargon for "webpage".  Here the page is not paper, it is a piece of information which we can see on a computer monitor at one time.  We can print it to make a real page.  But the information may not fit all on one page, and we can not change it when it is printed - we can change a web page.  So a webpage is not always the same even as a printed copy of that page.  This is a conceptual metaphor.  It can be confusing.  Someone who uses it is also likely to use other jargon.
 A page is also a boy or a young man who helps carry things and does small jobs for someone. Another word for this is a pageboy.
 To page someone is to contact that person on their pager: this is a small electronic machine which makes a sound or gives someone a message. This is usually to call someone for a certain reason, for example: to call them down somewhere, or to ask them for something.