Rāja yoga, the king of yogas, became in the medieval period a name for the yoga of meditation and samādhi, as distinct from haṭha yoga’s bodily disciplines. Vivekananda’s book Raja Yoga (1896) used it for Patañjali’s system, and the name has been used that way since.
Rāja yoga
The “royal yoga” of meditation: a later name for Patañjali’s classical yoga of the mind.
Also: Raja yoga