FTP is an initialism that stands for File Transfer Protocol. It is a communication system that allows transferring files between computers. If a user is granted access, with a username and password, it’s possible to access a remote computer on a network (most often a server, called an FTP-host) where the user is then able to either get or receive files.
An FTP connection is often used to access a web server to upload or download files for maintaining a website.