1. alien-not contained in or deriving from the essential nature of something; an economic theory alien to the spirit of capitalism; the mysticism so foreign to the French mind and temper; jealousy is foreign to her nature. foreign.
1 the quality of being hot; hotness: in physics, heat is considered a form of energy existing as the result of the random motion of molecules and is the form of energy that is transferred between bodies as a result of their temperature difference.  much hotness; great warmth: stifling heat.
Freebase(0.00 / 0 votes)Rate this definition: Central heating. A central heating system provides warmth to the whole interior of a building from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be an HVAC system.