Yoga Sutra 3.04 the triad – concentration, meditation, and samadhi
The triad (held) at the one place is saṃyama
The triad – concentration, meditation, and samādhi – held at the one place, is called saṃyama. The triple means directed on to a single object is called by the technical name of saṃyama.
What has been explained as the triad – concentration (dhāraṇā), meditation (dhyāna), and samādhi, held at the one place brought to completion at a single location, is called saṃyama. So he says: The triple means directed on to a single object is called by the technical name of saṃyama.
The triad, thus perfected stage by stage, is for the purposes of this work called by the technical name of saṃyama. In the various passages, when it is a question of grasping something desired to be known, or mastering something desired to be mastered, it is taught that some appropriate saṃyama should be known, and in all these passages, saṃyama is the technical term used for the triad. For instance, it will be said (III. 16): ‘From saṃyama on the three changes, knowledge of past and future’, and (III.44): ‘From saṃyama on their physical form, essential nature, subtle form, inherence, and purposefulness, conquest of the elements.’