Noun
The
branch
of
philosophy
which
studies
fundamental
principles
intended
to
describe
or
explain
all
that
is
,
and
which
are
not
themselves
explained
by
anything
more
fundamental
;
the
study
of
first
principles
;
the
study
of
being
insofar
as
it
is
being
(
Latin
: ''
ens in quantum ens
'').