[reconbot]

in the real sense of the word

[xellisx]

I would define anything that responds to remote request a server program, which then would make the system that runs that program a server. =)

[shazow]

A more interesting definition is that a server is something that is asymmetric from a client. Things that are peer to peer which are symmetric to each other are something special.

[humblebee]

By this definition, nothing that communicates with another process can be called serverless.

[TomMarius]

That definition is wrong.