Matter is any substance with mass and energy. Matter keeps its internal potential-energy (Ep) and sharing-energy (Es) as a (part of a) unity, until being forced out of the unity by external excess-energy (Ee >= Es) as a free particle. Matter shows its sharing-energy (Es) as gravity (F) or weight (W) or inertia-at-rest to its unity centre: Es = F = W. Matter does not show its potential-energy but transfers it between its sharing-energy and excess-energy; until and unless in a black hole, where matter transfers its potential-energy completely into sharing-energy Ep → Es, so that Ep = 0, and sharing-energy becomes infinity: Es = W = F → ∞, making the black hole into a physical singularity. Unity force or inertia (Fu = Es + Ee) is matter’s tendency to be unity, expressed as attracting while energy sharing in a unity (Ee = 0), as gravity or weight or inertia-at-rest to its unity centre; or repelling while excess-energy transferring out of the unity (Ee → Ee → 0), as inertia-in-motion or heat. That is, gravity is redefined as matter’s attraction to its unity centre, caused by its sharing-energy. Inertia is redefined and generalised to matter’s unity force, caused by its sharing-energy (as inertia-at-rest or gravity) and its excess-energy (as inertia-in-motion or heat). Matter moves relative to its unity centre, as its reference point, nullifying the base of the observational reference frame [7], making relativity a misconception. Matter moves to be unity by its unity force, in three dimensions, leaving a record or a trail. Space is the three dimensions of matter and of matter’s movements. Time is the record or trail of matter’s movements, not a dimension. Our timing systems and timers are based on matter’s time and are simulations of matter’s time. Space and time are properties of matter, not physical entities. Spacetime [8] is only a mathematical concept, not a physical one. Physically, a spacetime only pinpoints an event of matter’s movements. The universe only comprises matter and its movements in its three dimensions.