One of four words
Why energy.
Nothing comes from nothing. Whatever is here — atoms, stars, thoughts, this sentence — had to come from somewhere. There is no other option. Something must be ontologically prior, and that something must be capable of becoming everything else.
Modern physics has, more or less by accident, arrived at the same conclusion. Matter is condensed energy. Fields are energy. Forces are exchanges of energy. The solid world dissolves, when you look closely, into vibration and pattern. What we used to call substance turned out to be a behaviour of something more fundamental.
Energy is the most defensible candidate we have for the thing that has always been here.
I do not mean energy as the physicist measures it — joules and watts. I mean the broader word it always was. The capacity to be, to move, to do, to become. The source from which the rest is made.
This word alone, though, gives you a cold universe. Energy without consciousness, intelligence, or love is just a mechanism — a kind of engine running for no one, signifying nothing. That is why the description has four words. Energy is the foundation, but the foundation is not the whole house.