Yoga Sutras 3.4

Patanjali, explained by Swami Vivekananda

त्रयमेकत्र संयमः ॥

trayamekatra saṃyamaḥ

(These) three (when practised) in regard to one object is Samyama.

In plain words: When concentration, meditation, and absorption are all done on the same object, one after another, the combination is called Samyama.

Yoga Sutras 3.4

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Swami Vivekananda explains

When a man can direct his mind to any particular object and fix it there, and then keep it there for a long time, separating the object from the internal part, this is Samyama; or Dharana, Dhyana, and Samadhi, one following the other, and making one. The form of the thing has vanished, and only its meaning remains in the mind.