A measure of resistance of a Continuum body to compression.
It is defined as the ratio of the infinitesimal pressure increase to the resulting relative decrease of the density \rho or molar volume V_m:
| (1) | K = \rho \cdot \frac{\partial p}{\partial \rho} = - V_m \cdot \frac{\partial p}{\partial V_m} |
It is inverse to compressibility c:
| (2) | K = \frac{1}{c} |
It