"Upa" is the" go closer to", to move nearer to. The understanding of being closer to the Universe,
to be nearer to the teacher. The buddhi or the intellect has with understanding removed the
obstacles of ignorance between you and the teacher. As these obstacles dissolve
true learning of the function of the Universe is understood.

The last syllable, " shad", means 'to sit.' When you sit down, it means that you are ready to listen.
In this mental frame being totally relaxed one tries to understand the deeper aspects of Reality.
This "sitting down" is without the mind wandering and thinking about something else.
There is a deeper meaning to "shad". The settling-down of the mind.
The mind is fully receptive to what is being said.

The word "ni" which is in between, which connects "upa" and "shad" - indicates the level of sitting. "Ni" means sitting down at a level lower than that of the teacher. It literally means at the feet of the teacher, with humility, listening and imbibing. With an awareness that one does not know it all. Sitting voluntarily, with the intention of understanding the Supreme Truth.