Where the mind is engaged, meditation is the continuous movement of the instinct in that. The meaning of Dharana is to bring or fix the mind at one place, but the meaning of meditation is to keep the instinct running continuously wherever the mind is fixed. To be awake in it is meditation.

To know more about  Dhyaan listen to the podcast What is the logic with Dr Sheesham Aggarwal now available on all audio platforms.

To know more about Upnishad read the book- https://www.amazon.in/s?i=stripbooks&rh=p_27%3ADr.+Shisham+Bansal&ref=dp_byline_sr_book_1