GLOSSARY
Anomolia or anomaly, is the angular distance of a planet from its perihelion (that point of the orbit of a planet which is nearest to the sun) as seen from the sun.
Aequinoctium or the equinox, is the time in which days and nights are equal in the space of hours. There are two equinoxes: the spring equinox—c. 8 calends of April in the sign of Aries; and the fall equinox—c. 10 calends of October in the sign of Libra.
Aeras is derived from aera, aerae, which originally meant a given number, usually used in regard to money. The word was later extended to mean a number used in any calculation, and finally it came to mean a certain time from which subsequent times were counted, e.g., Anno Domini, after the Birth of Christ.
Coluri or the Colures, which are two circles in the heavenly sphere, passing through the poles of the world and cutting each other at right angles: the one passes through the equinoctial points of Aries and Libra and is called Colurus Aequinoctiorum or equinoctial colure; the other touches the solstitialia of Cancer and Capricorn and is called Colurus Solstitiorum or solstitial colure. They are called Colurus, which is translated as "mutilated tails," for the part which emerges in the Antarctic is not visible and is quasitruncated.
Ecliptica or the ecliptic, is an imaginary line in the heavens in which the sun was supposed to have performed its annual course.
Epicyclus or epicycle, is a small orb which, being fixed in the deferent of a planet, is carried along with its motion and yet, with its own peculiar motion, carries the body of the planet fastened to it round about its proper center.
Iris or the rainbow. In mythology, Iris was the daughter of Thaumatis and Electra, messenger of Juno of the goddesses and Jove of the gods.
Solstitium or the solstice, is that time when the sun seems to stand still for a short time: when the sign of Cancer enters the month of June (equivalent to the summer solstice, when the sun begins to recede from us); and when the sign of Capricorn enters the month of December (equivalent to the winter solstice, when the sun begins to accede to us).