Rāja yoga is a term with a variety of meanings depending on the context. In Sanskrit texts Raja yoga refers to the goal of yoga (which is usually samadhi) and not a method of attaining it. Classical tantric texts use the term raja yoga to refer to the consumption of sexual emissions in their practices. The term also became a modern retronym, when in the 19th-century Swami Vivekananda equated raja yoga with the Yoga Sutras of Patanjali.
Raja yoga is sometimes branded as or referred to as "royal yoga", "royal union", "sahaj marg", "classical yoga" and "aṣṭānga yoga". However, many of these are different practices from each other and from the historical concept of Raja yoga.
Example via www.ramdass.org: “Raja Yoga” by Swami Vivekananda