An archetype is an example of something. It is typically an original that is used as a model for things constructed after it. Eliade uses the word archetype to discuss how everything that people build, make and practice is according to some sort of model that came before it. He says archetypes give reality and validity to things in life.
“This participation by urban cultures in an archetypal model is what gives them their reality and their validity.”
“For the moment, what we wish to emphasize is the fact that the world which surrounds us, civilized by the hand of man, is accorded no validity beyond that which is due to the extraterrestrial prototype that served as its model. Man constructs according to an archetype.”
From Eliade, “‘The Phenomenology of Religion,’ from The Myth of the Eternal Return” in God. Ed. Robinson. 2nd ed. Hackett, 2003.