"Universe"
is a word
derived from
the
Old French
univers,
which in turn comes from the
Latin
roots
unus
("one") and
versus
(a form of vertere, "to turn").
Based on observations of the
observable
universe,
physicists attempt to describe the whole
of space-time, including all
matter
and
energy
and events which occur, as a single
system corresponding to a mathematical
model.
