This is the 216th most frequent Japanese word.
下
"下" means "below," "under," or "down."
In this sentence, '下' refers to the physical location beneath something, in this case, the tree. It is used to denote the position of 'under' or 'below'.
木の下で休みましょう。
Let's rest under the tree.
Here, '下' indicates being under the guidance or control of something, showing dependence or hierarchy.
指示の下で動いてください。
Please act under the instructions.
In this context, '下' is part of the verb '下す' (kudasu), meaning 'to decide' or 'to draw a conclusion,' thus presenting a figurative placement or action.