Wordnet 3.0
NOUN (1)
1. 
 (thermodynamics) a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure; 
- Example: "enthalpy is the amount of energy in a system capable of doing mechanical work"[syn: heat content, total heat, enthalpy, H]
WordNet (r) 3.0 (2006):
heat content
    n 1: (thermodynamics) a thermodynamic quantity equal to the
         internal energy of a system plus the product of its volume
         and pressure; "enthalpy is the amount of energy in a system
         capable of doing mechanical work" [syn: heat content,
         total heat, enthalpy, H]