The first part of a pathname the name of the disk and, if you like, the name of a subdirectory. Applications that ask you to type a pathname usually let you set a prefix so you don't have to type the complete pathname every time you want to work with a document on a particular disk or in a particular subdirectory. Once the prefix is set, all you do is type the rest of the pathname.
A prefix is used as the first part of certain kinds of name. A prefix is either a function call or a name.
A Host record field. An optional string which follows the Host name in a Midgard targeted URL. It may be seen as a prefix to the requested Page or as a suffix to the Host name. Different prefixes enable separate virtual Hosts with the same Host name and port number.
Item name prefixes can be used for two purposes. Grouping items for validation. Having more than one item on the screen with the same display name.
Driver prefix. The name of the driver must be the first characters of its standard entry point names; the combined names are used to dynamically link the driver into the kernel. Specified in the master.d file for the driver. Throughout this manual, the prefix pfx represents the name of the device driver, as in pfx open(), pfx ioctl().