In Vedic astrology (Jyotish), the zodiac belt — the apparent path of the Sun through the sky — is divided into 12 equal segments of 30 degrees each. Each segment is called a Rashi (sign). Unlike Western astrology which uses the tropical zodiac (tied to the equinoxes), Jyotish uses the sidereal zodiac (tied to fixed stars). The difference between the two, called Ayanamsha, is currently about 24 degrees. This means your Vedic sign is often one sign behind your Western sign.

Each Rashi carries a unique combination of element (tattva), quality (guna), and planetary lordship that defines its character. When a planet occupies a particular Rashi, it takes on the qualities of that sign — a planet in a fire sign acts differently from the same planet in a water sign. The Rashi where your Moon is placed determines your "Moon sign" (Rashi in everyday usage), which is the primary identity marker in Vedic astrology.

The ecliptic is the plane of Earth's orbit around the Sun, projected onto the celestial sphere. The Vedic zodiac divides this circle of 360 degrees into 12 equal sectors starting from the star Spica (Chitra) as the reference point for the Lahiri Ayanamsha. Each 30-degree sector is one Rashi. The sidereal position of any celestial body is computed by subtracting the Ayanamsha from its tropical longitude.

Every Rashi falls into one of three modalities (qualities) that describe how its energy expresses itself. These qualities cycle through the zodiac in a fixed pattern: Cardinal, Fixed, Mutable, Cardinal, Fixed, Mutable... This classification is crucial for predicting how planets will behave in a given sign.

Each Rashi is governed by one of four elements (Tattvas). The element cycle — Fire, Earth, Air, Water — repeats three times through the zodiac. Elements describe the fundamental nature of a sign's energy and strongly influence how planets placed in them will manifest their results.

Each Rashi is "owned" by a planet called its lord (Swami). The lord's condition in a chart profoundly affects all matters related to that sign. If the lord is strong (exalted, in own sign, or in a friend's sign), the sign's matters flourish. If the lord is weak (debilitated, combust, or in enemy territory), the sign's significations suffer. The Sun and Moon each own one sign; Mars, Mercury, Jupiter, Venus, and Saturn each own two signs. Rahu and Ketu do not own any Rashi in traditional Jyotish but co-rule certain signs in some schools.

Each planet has a specific degree where it reaches maximum strength (Uccha — exaltation) and a diametrically opposite degree where it is weakest (Neecha — debilitation). These are precise degrees, not just signs. A planet within a few degrees of its exact exaltation point produces powerful, beneficial results; near its debilitation point, its significations are weakened. The concept of Neecha Bhanga (cancellation of debilitation) provides important exceptions where a debilitated planet can still give good results.

In Vedic astrology, the zodiac is mapped onto a cosmic being called the Kalapurusha (Time Person). Aries rules the head and Pisces rules the feet, with each sign governing a specific body region in sequence. This mapping is used in medical astrology (Ayurvedic Jyotish) to identify vulnerable body parts. If a sign is afflicted by malefic planets, the corresponding body part may be prone to disease or injury.

Understanding how a planet behaves in different sign categories is fundamental to chart interpretation. The sign's element, quality, and lord all interact with the planet's own nature: