Here Patanjali introduces the word samadhi for the first time. He uses the word sabija samadhi. We have seen the word SA-vitarka sampatti and NI-vitarka sampatti, then he uses the words SA-vichara sampatti and NIR-vichara sampatti , now he uses the word SA-Bija samadhi. This is the first stage of union with the universal soul. We unite with the seed that created the universe which is in the unconscious state of the mind. It’s not that we become unconscious we are conscious but reach that stage where we reach the seed stage of the thoughts. The thoughts start ceasing slowly and slowly as we go deeper and deeper in meditation.