Definition.
An archetype is pattern which recurs in the human psyche across diverse eras and cultures. In many respects, it is similar to the concept of the Platonic Form. Thought to take its origin in the collective unconscious, the archetype manifests in dreams, fantasies and complexes, and in cultures as myth and folklore. Common examples: the hero, the Great Mother, the trickster.
We never encounter the archetype in its ‘pure’ form. This would be something akin to ‘meeting’ an idea. Instead, the archetype clothes itself in material we can perceive — images, memories, cultural artifacts, and so on — becoming what Jung called an archetypal image.
The complex, I suggest, is just such an archetypal image. In the case of the complex, the archetype has clothed itself in the material of the personal unconscious: our affects, memories, relationships, and so on. Once ‘dressed’ in this way, the archetype plays itself out in the situations and encounters in our lives.