A notebook is a blank book that you can write in. Students often carry notebooks, where they can take notes (and doodle). The pages in a notebook are often lined, so that you can write neatly.
A notebook (also known as a notepad, writing pad, drawing pad, or legal pad) is a book or stack of paper pages that are often ruled and used for purposes such as note-taking, journaling or other writing, drawing, or scrapbooking.