Tropical
every reader
What the tradition reads
The tropical zodiac fixes the first degree of Aries to the moment of the spring equinox every year, regardless of which constellation the Sun actually appears against at that instant, so that the tropical signs track the seasons rather than the visible stars and Aries always begins the astrological year exactly at the turn from winter to spring in the northern hemisphere. This is the standard zodiac of Western astrology, and the tradition built on it reads a sign's meaning as bound up with its seasonal position, Aries as the burst of new growth at spring's first turn, Cancer as the settled fullness of midsummer at the solstice, Capricorn as the hard, disciplined opening of winter, so that the sign's character and the season it inaugurates are treated as two expressions of the same underlying idea rather than as separate facts that happen to coincide. Because the tropical zodiac ignores the slow drift of the equinox against the background stars, a tropical sign and the constellation of the same name have moved well apart from one another since the system was fixed, a divergence the sidereal zodiac exists specifically to correct for, though the tropical tradition does not treat this divergence as an error needing correction at all.
The story
Tropic comes from the Late Latin tropicus, itself from the Ancient Greek tropikos, of or pertaining to a turn, a change, or the solstice, which is in turn built on tropē, a turning; tropical is simply tropic with the adjectival ending -al added. The same root names the Tropic of Cancer and the Tropic of Capricorn, the parallels of latitude at 23 degrees 26 minutes north and south of the equator marking the farthest points at which the Sun can stand directly overhead, the boundaries the torrid zone takes its name from. Western astrology has kept this seasonal anchor, the equinox itself rather than any star, as the zero point of Aries since the tropical and sidereal zodiacs last stood aligned, roughly two thousand years ago, when the vernal equinox still fell near the first degree of the constellation Aries in the visible sky, an alignment long since undone by the slow drift the sidereal zodiac tracks and the tropical zodiac by design does not.
Written from
Corpus key glossary:tropical.