The Collaborative International Dictionary of English v.0.48:

Conductivity \Con`duc*tiv"i*ty\
   (k[o^]n`d[u^]k*t[i^]v"[i^]*t[y^]), n.
   The quality or power of conducting, or of receiving and
   transmitting, as heat, electricity, etc.; as, the
   conductivity of a nerve.
   [1913 Webster]

   Thermal conductivity (Physics), the quantity of heat that
      passes in unit time through unit area of a plate whose
      thickness is unity, when its opposite faces differ in
      temperature by one degree.
      [1913 Webster]

WordNet (r) 3.0 (2006):

conductivity
    n 1: the transmission of heat or electricity or sound [syn:
         conduction, conductivity]