An artifact is an object created or modified by humans. It can be a relic of a former civilization, or of an earlier time period of an extant civilization. Artifacts are objects made by human hands, for a particular purpose: thus, archaeologists use artifacts to ascertain facts about an earlier human civilization. They are used to form the basis of an inferential process. For example, an ankh found in a sarcophagus in Egypt would allow archaeologists to draw inferences about Egyptian burial practices.
In roleplaying games, an artifact often refers to a magical item of considerable power.