This word is being used with a variety of different meanings.
In general, an archetype is a universal idea or exemplar of a principle. We could say that Plato's world of ideas is populated with archetypal forms. We could say that Perseus embodies the heroic archetype.
Ideals of religion, popular tales and legends seem to coalesce around recurring patterns and characters. The Arthurian mythos or the idea of a risen savior god are examples. A story told and retold tends to converge towards an archetypal form.
4th Way derived work deals with archetypes in an enneagram derived theory of personality, for example. Gurdjieff himself acknowledged that there exists a certain human typology having to do with archetypes but discussing such in detail would only lead to useless speculation and wiseacring, unless the student were much more advanced than those he had.
In Jungian psychology, man has a collection of personal archetypes that manifest variously in his conscious and subconscious functioning. These include shadow, anima/animus, syzygi and others. For example, the shadow of man is the repository of normally suppressed dark intentions, anima/animus is the representation of a form of the opposite sex, also the suppressed characteristic of the opposite sex in the self etc. Jung sees the unconscious as populated by such vague but somehow universal archetypes. In addition to this, there are transpersonal or global archetypes, a sort of racial or species memory of universal forms.
In the Ra material, the Tarot is analyzed in terms of archetypes. Any process of development or creation is seen to involve these archetypes: the Matrix, a sort of prime material or womb or blank canvas, a potentiator, one that defines the possible forms that may arise out of the matrix, the catalyst which is the cause of arising, the experience which is that which arises, the significator which is a choice of semantic interpretation, the transformation which is the next result and the great way which is a sort of synthesis. The concept is multifaceted and complex. See Book IV of Law of One.
Many sources use the word but often use a somewhat different, situation specific set of basic and derived archetypes. There is no universal dictionary of archetypes per se.