So please don't be offended or put off by any definition that seems either patronising or overly technical. The program that you use to view World Wide Web pages and do other internet related tasks. A client would normally only take in information or give out information that it had created, such as an email message. It would not distribute information like a server would. They are normally represented by underlined text and a blue font if you haven't clicked on them before.
Email clients connect to a POP server to retrieve new mail messages.
Your POP server is the part of an email server package which receives mail addressed to you. Your mail is stored on the server until you log on to the POP server and collect it. The POP server may reside on your local network or on the network of your Internet Service Provider. A particular staff member then uses and email client package which connects to DPOP to retreive their new messages. A server normally performs access checks to control the acces to the information it stores.