Artefact

An artefact is a single identifiable unit. Artefacts may be composites (consisting of other artefacts) or atomic (considered indivisible). Whether artefacts are considered composite or atomic may be dependent upon the context in which the artefact is defined and used.

An artefact has no history, but may appear as one artefact in a version graph.

Examples
A simple example of an artefact, from the software development realm, is a specific version of a file; version 1 of file1.c. Note that file1.c is not an artefact because this may refer to any of a number of versions of the file file1.c.

A less formal example of an artefact is 'the 30 inch monitor sitting on my desk in my office at 16:43 25th Feb 2012'. Although not especially helpful for most purposes, this specification is absolutely unique (it limits the monitor in question to the one on my desk 'at 16:43 25th Feb 2012' rather than any other time, if further limits it to the 30 inch monitor rather than the 24 or 22 inch monitors that happen to be sitting on my desk at that time, and 'my desk in my office' further limits the specification such that only one monitor in all of time and space occupies this unique specification). Again, this specification is lacking in all sorts of ways, but it does qualify this specific monitor as an artefact.

Discussion
The word artefact is used in order to avoid terminological problems associated with other terms used by the IT community. Specifically, terms like module, file, item, configuration item, and component, each have a specific meaning (this meaning is often contended and context dependent, making them less useful without careful qualification). Artefact is used to represent all of these terms.