Glossary
D
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, Y, Z

Day Houses—Refers to the Seventh to Twelfth Houses (six in all) located above the horizon.
Day Rulers—The Sun (Sunday), the Moon (Monday), Mars (Tuesday), Mercury (Wednesday), Jupiter (Thursday), Venus (Friday), and Saturn (Saturday).
Daylight-Saving Time—A local time variation that must be considered when calculating a chart.
Debility—A weak condition of a planet. See Essential Dignitaries and Debilities.
Decan, Decanates—A division of the signs into 10° units with different rulers. Also known as 'face'. See Essential Dignities and Debilities.
Decile Aspect—An aspect 36 ° of arc, arising from a division of the 360° zodiac into tenths. Sometimes called the semi-quintile.
Declination—THe arc of measurement in degrees north or south of the equator.
Degree—A degree is 1/360th of a circle. In astrology, degrees are the common unit of measurement.
Delineation—Meaning 'to draw a line'; in astrology it means to paint a portrait or interpret a horoscope.
Derived Houses—A method of renumbering the houses in horary astrology.
Descendant—The opposite point from the ascendant — the western horizon and the cusp of the Seventh House. It describes interactions with others.
Detriment—When a planet is in the sign opposite of the sign it rules, the planet is in detriment. Note that the 'opposite sign' is in relation to the sign that the planet ruled before the discovery of Uranus, Neptune, and Pluto. See Essential Dignities and Debilities. See Also Ruler.
Diamond—A mathematical point that corresponds to the position of the Sun when it is at perihelion.
Dignity—See Essential Dignities and Debilities.
Direct Motion—(Normal) movement of a planet in the order of the signs of the zodiac (Aries, Taurus, Gemini, and so on). Retrograde motion is opposite to direct motion.
Direct Station—The point where a stationary planet begins direct motion.
Dispositor—The dispositor of a planet is the ruler of the sign in which the planet is placed.
Diurnal—Meaning 'of the day'.
Domal Dignity—Refers to a planet in its own ruling house and the positive effects of this position.
Dome—See Zenith.
Dragon's Head—The Moon's North Node. See Moon Nodes.
Dragon's Tail—The Moon's South Node. See Moon Nodes.