A separately executable configuration of a server or other software entity on a given host. With a single installed set of binary files, it is possible to create multiple instances of Netscape servers that can be run and accessed independently of each other.

A Calendar Server configuration of one or more server processes. Multiple Calendar Server instances can be configured per server.

A distinct execution of a server process on a computing node. In general, multiple instances of a server can run on a single node or on multiple nodes, and each instance can be configured independently.

a complete and independent installation of SQL Server on a given server

An implementation of TASE.2 executed in either the client or the server role.

It means application server and each one has its own set of work processes.

See directory server instance.

An instance is a single configuration of an HTTP Server type.