A database is the information that makes up a dynamic website. It is stored in a grid with columns and rows. A column will have a relation in that it may be all the cities etc. a row may have relation in that it may be related columns such as a persons last and first name or other things about that person.

A dynamic website is one in which each page or screen that you see is not made up or assembled until the user requests it on their computer at home or in their office.