In Sanskrit, nadi can carry the sense of a channel, flow, or subtle division. The idea of progressively finer divisions is deeply embedded in Jyotisha. The zodiac, for example, can first be divided into 12 signs, each of 30 degrees. These provide broad “blocks” through which planetary positions are interpreted. The same celestial circle can then be divided more finely.

A familiar example is the division into 27 Nakshatras, each measuring 13°20′ (13.333…°). Each Nakshatra is further divided into four padas, producing still finer units for interpretation. Beyond these, classical Jyotisha contains numerous other divisions, or vargas, used for increasingly specific calculations. Among the very fine divisions is the Nadi Amsha, which in one established scheme divides each 30-degree sign into 150 parts of 12 arc-minutes each.

It is in this broader sense of fine divisions and channels of measurement that the term Nadi becomes particularly relevant. Various Nadi traditions place considerable emphasis on precise planetary degrees, Nakshatras, their padas, and other subtle divisions. Rather than treating the zodiac simply as twelve large compartments, they attempt to extract additional information from the finer structure within those compartments.

Different traditions use the word Nadi in different ways and employ different techniques. Some are strongly connected with Nakshatra-based calculations and very fine astronomical divisions, while others are associated with distinctive predictive methods and textual traditions.

The palm-leaf Nadi tradition is another important meaning of the term. In this tradition, collections of manuscripts—famously associated with places such as Tamil Nadu—are believed to contain readings concerning individuals and their lives. Practitioners traditionally identify a relevant leaf through a process involving personal clues or identifying information and then interpret the text for the seeker. A written prediction would still require some system of determination or underlying mechanism, which could potentially be based on finer divisions of the zodiac.

Thus, Nadi Astrology may refer to a family of astrological traditions involving fine divisions and specialised calculations, while Nadi astrology in the palm-leaf sense refers to a particular manuscript-based predictive tradition.