In both archetypal cosmology and traditional astrology, the term planet, reflecting its etymological roots in ancient Greek, has a wider connotation than its usual astronomical definition. As Richard Tarnas explains, "The ancient Greek root for the word 'planet' meant 'wanderer' and signified not only Mercury, Venus, Mars, Jupiter, and Saturn but also the Sun and Moon, i.e., all the visible celestial bodies that, unlike the fixed stars, moved through the skies in ways that differed from the simple motion and eternal regularity of the diurnal westward movement of the entire heavens. Though a distinction is often made between planets and luminaries, the astrological tradition has generally retained the original more encompassing meaning, referring to the Sun and Moon as planets" (Tarnas, Cosmos and Psyche, 504-505).

As a matter of both tradition and convenience, in the Archai journal the terms planet or planetary archetype will refer to the Sun and the Moon, Mercury, Venus, Mars, Jupiter, and Saturn as well as the three modern planets, Uranus, Neptune, and Pluto.

See also Dwarf Planets, Plutoids, and Pluto's Status as a Dwarf Planet.

The concept of planetary archetypes is highly complex. Briefly stated, however, a planetary archetype may be thought of as a universal principle with a defined range of general thematic meanings and qualities. Each principle is associated with a specific planet. Planetary archetypes are conceived as dynamic, creative, ordering principles that appear to give an a priori form and thematic content to human experience. For more in-depth discussions of the meaning of planetary archetypes and their archetypal formative function, see one of the following: See Planetary Archetypes for detailed descriptions of the archetypal themes associated with each planet.

In archetypal astrology, the term archetypal refers primarily to the set of qualities, themes, characteristics, impulses, and phenomena that relate to one or more of the planetary archetypes. Within this context, to describe something as archetypal or in archetypal terms is to refer to the universal underlying themes evident within concrete particulars.

When two planets move into alignment to form one of the major aspects or are in alignment in a natal chart, the planetary archetypes associated with these planets are said to form an archetypal complex, which reflects themes associated with both archetypes. Thus, if the planets Saturn and Neptune are in alignment, the resultant Saturn-Neptune complex reflects themes associated with the dynamic interaction of the Saturn principle and the Neptune principle.

Discussing planetary alignments during specific historical periods, O'Neal writes: "phenomena observed during such periods demonstrate characteristics of both archetypes in such a way that the two archetypes associated with those planets may be thought to create an archetypal complex. . . . In a sense, the two archetypes seem to activate each other with one archetype inflecting the other in characteristic ways and vice versa" (O'Neal, "Seasons of Agony and Grace," 51).

Tarnas describes an archetypal complex as "a coherent field of archetypally connected meanings, experiences, and psychological tendencies—expressed in perceptions, emotions, images, attitudes, beliefs, fantasies, and memories, as well as in synchronistic external events and historical and cultural phenomena—all of which appear to be informed by a dominant archetypal principle or combination of such principles. An archetypal complex can be conceived of as the experiential equivalent of a force field or a magnetic field in physics, producing an integrated pattern or gestalt out of many diverse particulars. Any given archetypal complex always contains problematic and pathological shadow tendencies intertwined with more salutary, fruitful, and creative ones, all of which inhere in potentia in each complex" (Tarnas, Cosmos and Psyche, 105).

The study of the correlations between planetary alignments and archetypal themes in human experience. Archetypal astrology combines an understanding of archetypal principles drawn from the depth psychology of C. G. Jung, James Hillman, and Stanislav Grof with techniques and interpretive methodologies drawn from astrology, in both its ancient and modern forms. For more on archetypal astrology, see Le Grice, "The Birth of a New Discipline," Archai: The Journal of Archetypal Cosmology, vol. 1:1 (2009).

A multidisciplinary subject drawing on scholarship from many areas such as astrology, depth psychology, history, philosophy, cosmology, religious studies, cultural studies, the arts, and the new sciences. It is a field of inquiry that includes the analysis of astrological correlations (archetypal astrology), but that goes beyond this to address the theoretical basis of these correlations and their implications for the wider world view.

The application of the techniques, methodology, and interpretive guidelines of archetypal astrology to the analysis of trends, cycles, and patterns of history. Archetypal historiography as a methodology combines two primary modes of inquiry: detailed historical research and the study of planetary correlations in relation to the archetypal analysis of history. In an expanding and deepening hermeneutic circle, the study of the historical and cultural phenomena illuminates the archetypal complexes associated with the planetary alignments, and the archetypal analysis illuminates the historical data.

For more on archetypal historiography, see O'Neal, "Archetypal Historiography: A New Historical Approach," Archai: The Journal of Archetypal Cosmology, vol. 1:1 (2009).

Within the context of archetypal astrology and archetypal cosmology, the term multivalence refers to the multitude of ways in which an archetype expresses itself within individual human experiences, the events of world history, works of art, cultural movements, or historical epochs, while remaining consistent with a central core of meaning. "The Saturn archetype can express itself as judgment but also as old age, as tradition but also as oppression, as time but also as mortality, as depression but also as discipline, as gravity in the sense of heaviness and weight but also as gravity in the sense of seriousness and dignity" (Cosmos and Psyche, 87). In other words, the concept of archetypal multivalence reflects the inherently irreducible nature of archetypal expression, which renders futile all attempts to understand them as univocal or singular manifestations.

In addition to the essential multivalence of archetypal expression, the term multidimensional refers to the potential appearance of these expressions in multiple dimensions of human experience—subjective or objective, physical or psychological, immanent or transcendent, mythic or metaphysical, and so forth. The concept of archetypal multidimensionality reflects an understanding of the nature of archetypes as autonomous principles and essences that cannot be localized in a particular dimension of being, and in this sense, archetypes may be understood as simultaneously Homeric, Platonic, and Jungian. As Tarnas describes this aspect of archetypal expression,