Chart concepts
Natal chart glossary
This page collects the terms that appear in the chart and in the reading, with short explanations. It is a reference, not a textbook: if you need to understand more deeply, each group of terms has a link to a detailed article.
The basis of the chart
General concepts with which any reading begins. More in the article what a natal chart is; signs, elements and the modalities of the signs are covered in the article signs, elements and modalities.
| Term | What it is |
|---|---|
| Natal chart | A diagram of the sky at the moment and place of birth: the positions of the planets in signs and houses and the links between them. It is a basis for interpretation, not a forecast of events |
| Chart factor | Any single element on which an interpretation rests: a planet’s sign, its house, an aspect, the Ascendant. Every statement in the reading is tied to a specific factor |
| Zodiac sign | One of twelve 30° sectors along the Sun’s path across the sky. The sign shows the manner in which a planet’s theme is expressed. Signs are not constellations but divisions of a circle |
| Element | A group of three signs of a similar character: fire (Aries, Leo, Sagittarius), earth (Taurus, Virgo, Capricorn), air (Gemini, Libra, Aquarius), water (Cancer, Scorpio, Pisces) |
| Modality of the signs | A division of the signs by way of acting: cardinal signs begin (Aries, Cancer, Libra, Capricorn), fixed signs sustain (Taurus, Leo, Scorpio, Aquarius), mutable signs adapt (Gemini, Virgo, Sagittarius, Pisces). It is also known as the quality of a sign |
| House | One of the twelve sectors of the chart, counted from the Ascendant. The house shows the area of life in which a planet’s theme is expressed |
Points and angles
These points depend on the time and place of birth. The Ascendant is described in detail in the article the Ascendant in the natal chart, the other angles in the article the angles of the natal chart, and the houses in the article houses in the natal chart.
| Term | What it is |
|---|---|
| Ascendant (ASC) | The sign and degree of the zodiac rising over the eastern horizon at the moment of birth. In interpretation — the manner of carrying oneself and entering something new. The start of the first house |
| Midheaven (MC) | The highest point of the zodiac above the place of birth. In interpretation — direction, goals and public role. The start of the tenth house |
| Descendant (DSC) | The point opposite the Ascendant, where the zodiac sets below the western horizon. The sign of the Descendant is opposite the sign of the Ascendant; we do not interpret it separately |
| IC | The point opposite the Midheaven — the lowest point of the zodiac below the place of birth. The start of the fourth house; we do not interpret it separately |
| Chart ruler | The planet that, by the traditional table, rules the sign of the Ascendant (for example Mars for Aries, Venus for Taurus). It is considered together with the house it occupies |
| Retrograde motion | The apparent movement of a planet backwards through the zodiac as seen from Earth. We take it into account only for Mercury, Venus and Mars |
Retrograde motion in a natal chart is not the same as “Mercury retrograde” in the news: the chart records the state at the moment of birth, not current events. More in the article retrograde planets in the natal chart.
Links between planets
Aspects show how the themes of planets interact. All five aspects, their orbs and examples are in the article aspects in the natal chart.
| Term | What it is |
|---|---|
| Aspect | A particular angle between two planets. We use five aspects: the conjunction, sextile, square, trine and opposition |
| Orb | The permitted deviation of an angle from the exact value of an aspect. For the Sun and Moon it is wider than for the other bodies |
| Conjunction | An aspect of 0°: the planets stand close together and their themes merge |
| Sextile | An aspect of 60°: an opportunity for the themes to cooperate |
| Square | An aspect of 90°: tension that requires effort and often becomes a source of development |
| Trine | An aspect of 120°: agreement of the themes, ease |
| Opposition | An aspect of 180°: polarity, two opposite themes between which a balance has to be sought |
Calculation
Terms that explain why charts from different services may differ. Exactly how we calculate is described on the methodology page.
| Term | What it is |
|---|---|
| Ecliptic | The Sun’s visible path across the sky over the course of a year. The zodiac signs are measured along the ecliptic |
| Tropical zodiac | A zodiac in which the signs are measured from the point of the spring equinox. We use it for all charts. The sidereal zodiac is measured differently and gives different signs for many planets |
| Placidus | One of the systems of dividing the sky into houses, which we use. Other systems, such as Koch, equal houses or whole-sign houses, give different house boundaries |
| Geocentric positions | The positions of the bodies as they are seen from Earth. This is how traditional interpretation describes them |
| Unknown factor | A factor that cannot be determined because the birth time is inexact or unknown. The reading says nothing about it: the unknown does not turn into a conclusion |
What next
The easiest way to see these terms in your own chart is by building your chart. And if you want to go back to the basics, open the article how to read a natal chart.
Your chart by these rules
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