Claire Dehon wrote today that, "After all, Rome, where the word comes
from, was divided in four "tribus" (I do not know the plural of the
word, if there is one). Then it just meant an administrative
division!" But we are not in Rome, living in the whatever century it
was when it was divided into tribus.
Connotations change with times and contexts, and that is the whole
reason for the debate. So, while it is sometimes helpful to look at
etymologies as a starting point, we can't be content to leave it at
that.