A name server is a computer configured to translate domain names on the Internet into IP addresses. This is necessary because people can remember domain names more easily than IP addresses. When you type a domain name into a web browser, the name server will look up the IP address and direct the browser to the correct website.
Informally speaking, a name server is a kind of “phone book” for the Internet. Just as a phone book helps you look up a person based on their name, a name server helps you look up a website based on its domain name. When you type a domain name into your web browser, the name server will look in the “phone book” to see which IP address is associated with the domain name and direct the browser to the correct website.