A more or less superficial layer of the unconscious is undoubtedly personal. I call it the "personal unconscious". But this personal layer rests upon a deeper layer, which does not derive from personal experience and is not a personal acquisition but is inborn. This deeper layer I call the "collective unconscious". I have chosen the term "collective" because this part of the unconscious is not individual but universal; in contrast to the personal psyche, it has contents and modes of behaviour that are more or less the same everywhere and in all individuals.

p. 3-4 - The Archetypes and the Collective Unconscious (1934)