So in my coursebook it says enthalpy is a property that accounts for the increase in internal energy and the accompanying work done by the system and that its equal to the sum of the internal energy $U$ and product of pressure $P$ and volume $V$. Also on the net, mostly on the internet it says:
A thermodynamic quantity equivalent to the total heat content of a system. It is equal to the internal energy of the system plus the product of pressure and volume.
And where it explains in other words I don't quite understand, e.g. as on Wikipedia. So please I would like anyone of you to explain (in beginner terms) that what is the meaning of enthalpy and heat content as used in the definition above.