Based on the arabic lexicon, the root word means:
1 - Close consecutivenss between rain drops, as if they were falling almost together or right after the other.
2 - Hanging of a rope around he neck of a person coupled with another.
3 - Two things in continuation without interruption.
4 - Overtake as if you catch up with someone or something or attain something as if in revenge or some stage in a certain quest for something.
5 - To follow up with amends to some previous error or to follow up on something.
6 - There are other meanings however they seem less relevant.
After looking at all these meanings and with todays knowledge of moon phases, what makes sense to me is we know the sunlight is always reflected on the moon surface (the side which faces earth) yet the moon is not always visible to us because of its position relative earth in its revolution. Like a new moon and full moon are both when the moon is fully in front of our line if sight yet the position of the earth relative to the moons orbit either conceals it or reveals it. So the sun does not at anytime hide the moon from us or over power or overtake it. Its the earth position relative to the moons orbit which causes it.
Now how would the Sahaba RA have understood this, I still wonder. What meaning would they have taken away from it. I guess the more classical tafsirs such as Kathir would be closest to it though we may today understand the verse with a whole new perception, OR NOT?