Dhruva is the twelfth nityayoga, and its name means fixed, firm, and constant, the same word names the pole star, Dhruva, the unmoving point of the sky. It is one of the auspicious yogas, favourable for undertakings meant to be permanent and unshakeable, such as laying foundations and making lasting commitments. Reckoned from the summed longitude of Sun and Moon divided into twenty-seven parts, it advances as the lights draw apart. In the panchanga it lends its quality of fixity to the reckoning of an auspicious moment. These are the conventions of the calendar tradition, which fixes the character of each yoga; here the very name evokes the steadfastness the tradition seeks for enduring works.
Because dhruva names both this yoga and the pole star, the word carries an unusually concrete astronomical referent compared with most of the twenty-seven, whose names describe abstract qualities, states or deities rather than a specific fixed point in the sky; the pole star's genuine celestial fixity, its position scarcely changing while the rest of the sky wheels around it nightly, gives Dhruva's association with permanence and reliability an observational grounding rather than a purely symbolic one. The pole star Dhruva is also the subject of a well-known devotional legend, the boy sage whose steadfast penance won him his fixed place in the heavens, a story frequently invoked wherever the theme of unwavering constancy is illustrated in later religious literature.